Angina Pectoris

 

Article Last Updated: Dec 19, 2007

AUTHOR AND EDITOR INFORMATION

Jamshid Alaeddini, MD, FACC, Clinical Cardiac Electrophysiologist, Inland Cardiology Associates
Jamshid Alaeddini is a member of the following medical societies: American College of Cardiology, American Heart Association, and Heart Rhythm Society
Coauthor(s): Jamshid Shirani, MD, FACC, FAHA, Consulting Staff, Director of Cardiovascular Fellowship Program, Department of Medicine, Division of Cardiology, Geisinger Medical Center

INTRODUCTION

Background

Angina pectoris is the result of myocardial ischemia caused by an imbalance between myocardial blood supply and oxygen demand. Angina is a common presenting symptom (typically, chest pain) among patients with coronary artery disease. A comprehensive approach to diagnosis and to medical management of angina pectoris is an integral part of the daily responsibilities of physicians.

Pathophysiology

Myocardial ischemia develops when coronary blood flow becomes inadequate to meet myocardial oxygen demand. This causes myocardial cells to switch from aerobic to anaerobic metabolism, with a progressive impairment of metabolic, mechanical, and electrical functions. Angina pectoris is the most common clinical manifestation of myocardial ischemia. It is caused by chemical and mechanical stimulation of sensory afferent nerve endings in the coronary vessels and myocardium. These nerve fibers extend from the first to fourth thoracic spinal nerves, ascending via the spinal cord to the thalamus, and from there to the cerebral cortex.

Recent studies have shown that adenosine may be the main chemical mediator of anginal pain. During ischemia, ATP is degraded to adenosine, which, after diffusion to the extracellular space, causes arteriolar dilation and anginal pain. Adenosine induces angina mainly by stimulating the A1 receptors in cardiac afferent nerve endings.

Heart rate, myocardial inotropic state, and myocardial wall tension are the major determinants of myocardial metabolic activity and myocardial oxygen demand. Increases in the heart rate and myocardial contractile state result in increased myocardial oxygen demand. Increases in both afterload (ie, aortic pressure) and preload (ie, ventricular end-diastolic volume) result in a proportional elevation of myocardial wall tension and, therefore, increased myocardial oxygen demand. Oxygen supply to any organ system is determined by blood flow and oxygen extraction. Because the resting coronary venous oxygen saturation is already at a relatively low level (approximately 30%), the myocardium has a limited ability to increase its oxygen extraction during episodes of increased demand. Thus, an increase in myocardial oxygen demand (eg, during exercise) must be met by a proportional increase in coronary blood flow.

The ability of the coronary arteries to increase blood flow in response to increased cardiac metabolic demand is referred to as coronary flow reserve (CFR). In healthy people, the maximal coronary blood flow after full dilation of the coronary arteries is roughly 4-6 times the resting coronary blood flow. CFR depends on at least 3 factors: large and small coronary artery resistance, extravascular (ie, myocardial and interstitial) resistance, and blood composition.

Myocardial ischemia can result from (1) a reduction of coronary blood flow caused by fixed and/or dynamic epicardial coronary artery (ie, conductive vessel) stenosis, (2) abnormal constriction or deficient relaxation of coronary microcirculation (ie, resistance vessels), or (3) reduced oxygen-carrying capacity of the blood.

Atherosclerosis is the most common cause of epicardial coronary artery stenosis and, hence, angina pectoris. Patients with a fixed coronary atherosclerotic lesion of at least 50% show myocardial ischemia during increased myocardial metabolic demand as the result of a significant reduction in CFR. These patients are not able to increase their coronary blood flow during stress to match the increased myocardial metabolic demand, thus they experience angina. Fixed atherosclerotic lesions of at least 90% almost completely abolish the flow reserve; patients with these lesions may experience angina at rest.

Coronary spasm can also reduce CFR significantly by causing dynamic stenosis of coronary arteries. Prinzmetal angina is defined as resting angina associated with ST-segment elevation caused by focal coronary artery spasm. Although most patients with Prinzmetal angina have underlying fixed coronary lesions, some have angiographically normal coronary arteries. Several mechanisms have been proposed for Prinzmetal angina: focal deficiency of nitric oxide production, hyperinsulinemia, low intracellular magnesium levels, smoking cigarettes, and using cocaine.

Approximately 30% of patients with chest pain referred for cardiac catheterization have normal or minimal atherosclerosis of coronary arteries. A subset of these patients demonstrates reduced CFR that is believed to be caused by functional and structural alterations of small coronary arteries and arterioles (ie, resistance vessels). Under normal conditions, resistance vessels are responsible for as much as 95% of coronary artery resistance, with the remaining 5% being from epicardial coronary arteries (ie, conductive vessels). The former is not visualized during regular coronary catheterization. Angina due to dysfunction of small coronary arteries and arterioles is called microvascular angina. Several diseases, such as diabetes mellitus, hypertension, and systemic collagen vascular diseases (eg, systemic lupus erythematosus, polyarteritis nodosa), are believed to cause microvascular abnormalities with subsequent reduction in CFR.

The syndrome that includes angina pectoris, ischemialike ST-segment changes and/or myocardial perfusion defects during stress testing, and angiographically normal coronary arteries is referred to as syndrome X. Most patients with this syndrome are postmenopausal women, and they usually have an excellent prognosis. Syndrome X is believed to be caused by microvascular angina. Multiple mechanisms may be responsible for this syndrome, including (1) impaired endothelial dysfunction, (2) increased release of local vasoconstrictors, (3) fibrosis and medial hypertrophy of the microcirculation, (4) abnormal cardiac adrenergic nerve function, and/or (5) estrogen deficiency.

A number of extravascular forces produced by contraction of adjacent myocardium and intraventricular pressures can influence coronary microcirculation resistance and thus reduce CFR. Extravascular compressive forces are highest in the subendocardium and decrease toward the subepicardium. Left ventricular (LV) hypertrophy together with a higher myocardial oxygen demand (eg, during tachycardia) cause greater susceptibility to ischemia in subendocardial layers.

Myocardial ischemia can also be the result of factors affecting blood composition, such as reduced oxygen-carrying capacity of blood, as is observed with severe anemia (hemoglobin, <8 g/dL), or elevated levels of carboxyhemoglobin. The latter may be the result of inhalation of carbon monoxide in a closed area or of long-term smoking.

Recently, ambulatory ECG monitoring has shown that silent ischemia is a common phenomenon among patients with established coronary artery disease. In one study, as many as 75% of episodes of ischemia (defined as transient ST depression of >1 mm persisting for at least 1 min) occurring in patients with stable angina were clinically silent. Silent ischemia occurs most frequently in early morning hours and may result in transient myocardial contractile dysfunction (ie, stunning). The exact mechanism(s) for silent ischemia is not known. However, autonomic dysfunction (especially in patients with diabetes), a higher pain threshold in some individuals, and the production of excessive quantities of endorphins are among the more popular hypotheses.

Frequency

United States

Approximately 6.3 million Americans are estimated to experience angina. An estimated 350,000 new cases of angina occur every year. Each year, 1.1 million new and recurrent cases of an acute coronary event occur in this country, of which more than 40% are fatal. Roughly, more than 12 million Americans had a history of myocardial infarction (MI) and/or angina pectoris in the year 2000.

Mortality/Morbidity

Coronary artery disease is the single most common cause of death in the United States, accounting for almost one death per minute. More than half of those who die suddenly from coronary artery disease have no previous symptoms.

Race

The rate of angina pectoris in women older than 20 years ranges from 3.9% in non-Hispanic white women to 6.2% in non-Hispanic black women and 5.5% in Mexican American women. The rates of angina pectoris for men in the same ethnic groups are 2.6%, 3.1%, and 4.1%, respectively. Among American Indians aged 65-74 years, the rates (per 1000 persons) of new and recurrent heart attacks are 25.1% for men and 9.1% for women.

Sex

Angina pectoris is more often the presenting symptom of coronary artery disease in women than in men, with a female-to-male ratio of 1.7:1. It has a prevalence of 3.9 million in women and 2.3 million in men. The frequency of atypical presentations is also more common among women compared with men. Women have a slightly higher rate of mortality from coronary artery disease compared with men, in part because of an older age at presentation and a frequent lack of classic anginal symptoms. The estimated age-adjusted prevalence of angina is greater in women than in men.

Age

The prevalence of angina pectoris increases with age. Age is a strong independent risk factor for mortality.

 

CLINICAL

History

Most patients with angina pectoris report of retrosternal chest discomfort rather than frank pain. The former is usually described as a pressure, heaviness, squeezing, burning, or choking sensation. Anginal pain may be localized primarily in the epigastrium, back, neck, jaw, or shoulders. Typical locations for radiation of pain are arms, shoulders, and neck. Typically, angina is precipitated by exertion, eating, exposure to cold, or emotional stress. It lasts for approximately 1-5 minutes and is relieved by rest or nitroglycerin. Chest pain lasting only a few seconds is not usually angina pectoris. The intensity of angina does not change with respiration, cough, or change in position. Pain above the mandible and below the epigastrium is rarely anginal in nature.

• Ask patients about the frequency of angina, severity of pain, and number of nitroglycerin pills used during angina episodes.
• Angina decubitus is a variant of angina pectoris that occurs at night while the patient is recumbent. Some have suggested that it is induced by an increase in myocardial oxygen demand caused by expansion of the blood volume with increased venous return during recumbency.
• The Canadian Cardiovascular Society grading scale is used for classification of angina severity, as follows:
• • Class I - Angina only during strenuous or prolonged physical activity
  • Class II - Slight limitation, with angina only during vigorous physical activity
  • Class III - Symptoms with everyday living activities, ie, moderate limitation
  • Class IV - Inability to perform any activity without angina or angina at rest, ie, severe limitation
• The New York Heart Association classification is also used to quantify the functional limitation imposed by patients' symptoms, as follows:
• • Class I - No limitation of physical activity (Ordinary physical activity does not cause symptoms.)
  • Class II - Slight limitation of physical activity (Ordinary physical activity does cause symptoms.)
  • Class III - Moderate limitation of activity (Patient is comfortable at rest, but less than ordinary activities cause symptoms.)
  • Class IV - Unable to perform any physical activity without discomfort, therefore severe limitation (Patient may be symptomatic even at rest.)
• Unstable angina is defined as new-onset angina (ie, within 2 mo of initial presentation) of at least class III severity, significant recent increase in frequency and severity of angina, or angina at rest.

Physical

• For most patients with stable angina, physical examination findings are normal. Diagnosing secondary causes of angina, such as aortic stenosis, is important.
• A positive Levine sign (characterized by the patient's fist clenched over the sternum when describing the discomfort) is suggestive of angina pectoris.
• Look for physical signs of abnormal lipid metabolism (eg, xanthelasma, xanthoma) or of diffuse atherosclerosis (eg, absence or diminished peripheral pulses, increased light reflexes or arteriovenous nicking upon ophthalmic examination, carotid bruit).
• Examination of patients during the angina attack may be more helpful. Useful physical findings include third and/or fourth heart sounds due to LV systolic and/or diastolic dysfunction and mitral regurgitation secondary to papillary muscle dysfunction.
• Pain produced by chest wall pressure is usually of chest wall origin.

Causes

• Decrease in myocardial blood supply due to increased coronary resistance in large and small coronary arteries
• • Significant coronary atherosclerotic lesion in the large epicardial coronary arteries (ie, conductive vessels) with at least a 50% reduction in arterial diameter
  • Coronary spasm (ie, Prinzmetal angina)
  • Abnormal constriction or deficient endothelial-dependent relaxation of resistant vessels associated with diffuse vascular disease (ie, microvascular angina)
  • Syndrome X
  • Systemic inflammatory or collagen vascular disease, such as scleroderma, systemic lupus erythematous, Kawasaki disease, polyarteritis nodosa, and Takayasu arteritis
• Increased extravascular forces, such as severe LV hypertrophy caused by hypertension, aortic stenosis, or hypertrophic cardiomyopathy, or increased LV diastolic pressures
• Reduction in the oxygen-carrying capacity of blood, such as elevated carboxyhemoglobin or severe anemia (hemoglobin, <8 g/dL)
• Congenital anomalies of the origin and/or course of the major epicardial coronary arteries
• Structural abnormalities of the coronary arteries
• • Congenital coronary artery aneurysm or fistula
  • Coronary artery ectasia
  • Coronary artery fibrosis after chest radiation
  • Coronary intimal fibrosis following cardiac transplantation
• Risk factors
• • Major risk factors for atherosclerosis: These include a family history of premature coronary artery disease, cigarette smoking, diabetes mellitus, hypercholesterolemia, or systemic hypertension.
  • Other risk factors: These include LV hypertrophy, obesity, and elevated serum levels of homocysteine, lipoprotein (a), plasminogen activator inhibitor, fibrinogen, serum triglycerides, or low high-density lipoprotein (HDL).
  • Metabolic syndrome: This has recently been characterized by the presence of hyperinsulinemia (fasting glucose level, ³110 mg/dL), abdominal obesity (waist circumference, >40 in for men or >35 in for women), decreased HDL cholesterol levels (<40 mg/dL for men or <50 mg/dL for women), hypertriglyceridemia (>150 mg/dL), and hypertension (³130/85 mm Hg). Based on data from the 2000 US census, an estimated 47 million Americans have the metabolic syndrome. Patients with the metabolic syndrome have a 3-fold increased risk for coronary atherosclerosis and stroke compared with those without this syndrome.
• Precipitating factors: These include factors such as severe anemia, fever, tachyarrhythmias, catecholamines, emotional stress, and hyperthyroidism, which increase myocardial oxygen demand.
• Preventive factors: Factors associated with reduced risk of atherosclerosis are a high serum HDL cholesterol level, physical activity, estrogen, and moderate alcohol intake (1-2 drinks/d).

 

DIFFERENTIALS

Anemia
Anxiety Disorders
Aortic Dissection
Aortic Stenosis
Biliary Colic
Cardiomyopathy, Hypertrophic
Cholecystitis
Coronary Artery Atherosclerosis
Coronary Artery Vasospasm
Diabetes Mellitus, Type 1
Diabetes Mellitus, Type 2
Gastric Ulcers
Gastritis, Acute
Gastroesophageal Reflux Disease
Hiatal Hernia
Hypercholesterolemia, Familial
Hypercholesterolemia, Polygenic
Hypertension
Hyperthyroidism
Isolated Coronary Artery Anomalies
Kawasaki Disease
Mitral Regurgitation
Mitral Valve Prolapse
Panic Disorder
Pericarditis, Acute
Pleurodynia
Pneumothorax
Polyarteritis Nodosa
Pott Disease (Tuberculous Spondylitis)
Pulmonary Embolism
Pulmonary Hypertension, Primary
Pulmonary Hypertension, Secondary
Scleroderma
Systemic Lupus Erythematosus
Takayasu Arteritis
Toxicity, Cocaine
Varicella-Zoster Virus

Other Problems to be Considered

Esophageal spasm
Esophageal rupture
Costochondritis
Herpes zoster
Pneumonia with pleural involvement

 

WORKUP

Imaging Studies

• Chest radiograph findings are usually normal in patients with angina pectoris. However, they may show cardiomegaly in patients with previous MI, ischemic cardiomyopathy, pericardial effusion, or acute pulmonary edema. Calcification of coronary arteries frequently correlates with major coronary artery disease.
• Graded exercise stress testing is the most widely used test for the evaluation of patients presenting with chest pain. In patients with established stable angina pectoris, it also can provide prognostic information about the extent of disease.
• • Exercise stress testing can be performed alone and in conjunction with echocardiography or myocardial perfusion scintigraphy tests. Stress echocardiography has an overall sensitivity of 78% and specificity of 86%; myocardial perfusion scintigraphy has an overall sensitivity of 83% and specificity of 77%. Exercise stress testing alone generally has somewhat lower sensitivity and specificity, but it is cheaper and therefore is a reasonable choice in those with a low probability of disease.
  • These test results must be interpreted in the context of the likelihood of the presence of coronary artery disease determined from the patient's history and physical examination findings. In a population with low prevalence, the predictive abilities of these tests are low; however, in patients with a high likelihood of coronary artery disease, the predictive value is much higher.
• Stress echocardiography can be used to evaluate segmental wall motion during exercise. It detects changes in regional wall motion that occur during myocardial ischemia. Normal myocardium becomes hyperdynamic during exercise; ischemic segments become hypokinetic or akinetic.
• • Stress echocardiography has the advantage of simultaneous evaluation of LV function, cardiac dimensions, and valvular disease. It is especially useful in patients with baseline ECG abnormalities and those with systolic murmurs suggestive of aortic stenosis or hypertrophic cardiomyopathy.
  • It is also helpful for localizing ischemia and evaluating its severity.
  • Signs of severe coronary artery disease during exercise stress echocardiography include LV dilation, a decrease in global systolic function, and new or worsening mitral regurgitation. However, with dobutamine stress echocardiography, even in patients with severe coronary artery disease, the LV cavity may not dilate and global systolic function may improve.
  • A major problem with stress echocardiography is the technical difficulty with obtaining adequate images in some patients.
• Thallium Tl 201 and technetium Tc 99m sestamibi are the most frequently used myocardial perfusion scintigraphy tests. These tests are especially useful in patients with baseline ECG abnormalities, to localize the region of ischemia, and as prognostic indicators. The presence of increased lung uptake upon thallium imaging is associated with a poor prognosis. Increased lung uptake, together with poststress dilation of the LV and multiple perfusion defects, is suggestive of either left main coronary artery disease or severe 3-vessel disease. The number of affected myocardial segments is predictive of long-term survival. Smaller perfusion defects are usually associated with peripheral coronary artery lesions, which are associated with a better prognosis. The absence of perfusion defects even in the presence of symptoms indicates an excellent prognosis.
• The frequency of infarction or death is 1 case per 10,000 stress tests. Absolute contraindications include symptomatic cardiac arrhythmias, severe aortic stenosis, acute MI within the previous 2 days, acute myocarditis, or pericarditis. Discontinue the exercise stress test in the presence of chest pain, a drop in systolic blood pressure of more than 10 mm Hg, severe shortness of breath, fatigue, dizziness or near syncope, ST depression of more than 2 mm, ST elevation of at least 1 mm without diagnostic Q waves, or development of ventricular tachyarrhythmia.
• In recent years, coronary artery calcium (CAC) scoring by fast computed tomography (CT) has become more popular in clinical practice for risk assessment of patients with chest pain. Currently, electron-beam computed tomography (EBCT) and multi-detector computed tomography (MDCT) are the primary fast CT methods for CAC measurement. However, some controversy exists about the usefulness of this test.
• • In asymptomatic patients, analysis of the data from CAC scoring in patients with an intermediate Framingham risk score reveals that for a score of 400 or more, the patient's 10-year CAD risk would achieve a risk equivalent status similar to that noted with diabetes or peripheral arterial disease. Thus, finding a high CAC score in asymptomatic patients with an intermediate Framingham risk score (10-20% risk of CAD in 10 y) could be useful by resulting in a more aggressive management approach. However, unselected screening is of limited clinical value in asymptomatic patients who have a low Framingham risk score. On the other hand, assessment of CAC in asymptomatic patients with a high Framingham risk score (>20% risk of CAD in 10 y) has limited value since, based on current guidelines, these patients should be treated aggressively irrespective of their CAC scoring.
  • In symptomatic patients, exclusion of measurable CAC may be an effective tool before undertaking invasive diagnostic procedures or hospital admission. Patients with CAC scores of less than 100 have a low probability (<2%) of abnormal perfusion on nuclear stress tests, and a low probability (<3%) of obstructive CAD (>50% stenosis) on cardiac catheterization. Studies of large numbers of symptomatic patients demonstrated that the absence of CAC has a high negative predictive value of 96-100%. Thus, an individual with no coronary calcium (score _ 0) can be told with a high level of confidence that he or she has no obstructive angiographic coronary disease.
  • In patients with documented CAD, clinical monitoring of CAC progression through serial fast CT scanning to assess progression or regression of CAD is not recommended at this time.
  • Since most of current data regarding CAC are collected from patient population of mostly Caucasian men, the guidelines suggest caution in applying these findings to women and ethnic minorities.

Other Tests

• ECG is useful for evaluating persons with angina pectoris; however, findings are variable among patients.
• • Approximately 50% of patients with angina pectoris have normal findings after a resting ECG. However, abnormalities such as evidence for prior MI, intraventricular conduction delay, various degrees of atrioventricular block, arrhythmias, or ST-T–wave changes may be seen.
  • During an attack of angina pectoris, 50% of patients with normal findings after resting ECG show abnormalities. A 1-mm or greater depression of the ST segment below the baseline, measured 80 milliseconds from the J point, is the most characteristic change. Reversible ST-segment elevation occurs with Prinzmetal angina. Some patients with coronary artery disease may show pseudonormalization of the resting ECG ST-T–wave abnormalities during episodes of chest pain.
• Exercise with ECG monitoring alone is the initial procedure of choice in patients without baseline ST-segment abnormalities or in whom anatomic localization of ischemia is not a consideration.
• • Horizontal or down-sloping ST-segment depression of at least 1 mm, measured 80 milliseconds from the J point, is considered the characteristic ischemic response.
  • ST-segment depression of more than 2 mm at a low workload or that persists for more than 5 minutes after termination of exercise and a failure of blood pressure to rise or an actual drop in blood pressure are signs of severe ischemic heart disease and a poor prognosis.
  • Withhold beta-blockers for approximately 48 hours before the stress test, whenever possible. Patients on digoxin and those with LV hypertrophy with repolarization abnormalities more often show positive results. Exercise stress tests have lower sensitivity and specificity in women and in patients with left bundle-branch block.
  • Pharmacologic agents (eg, dobutamine, dipyridamole, adenosine) can be used in patients who are unable to exercise.
• Ambulatory ECG monitoring can be used for diagnostic purposes in patients with chest pain suggestive of Prinzmetal angina but is primarily used to evaluate the frequency of silent ischemia. Silent ischemia has been shown to be an independent predictor of mortality in patients with angina pectoris.

Procedures

• Selective coronary angiography is the definitive diagnostic test for evaluating the anatomic extent and severity of coronary artery disease.
• • Consider coronary angiography in symptomatic patients with inconclusive noninvasive study results, in survivors of sudden cardiac death, in those who are considered to have a poor prognosis based on the results of noninvasive studies, in those with occupational requirements for a definite diagnosis (eg, pilots), or in patients with coronary artery disease who are severely symptomatic despite maximal medical therapy.
  • In patients in whom Prinzmetal angina is suggested, provocative testing with ergonovine maleate during coronary angiography may be useful.
• Intra-aortic balloon counterpulsation can be used in patients who continue to have unstable angina pectoris despite maximal medical treatment. This procedure should be followed promptly by coronary angiography with possible coronary revascularization.
• In patients whose angina is refractory to medical therapy who are not suitable candidates for either percutaneous or surgical revascularization, enhanced external counterpulsation is a safe and noninvasive alternative therapy. It increases coronary perfusion and reduces myocardial oxygen demand by diastolic augmentation of the central aortic pressure. Several studies have shown that patients treated with enhanced external counterpulsation have a significantly reduced number of anginal episodes, improved exercise tolerance, and decreased daily use of nitroglycerin tablets. Its therapeutic effects on quality of life are noted to remain at 1-year follow-up.

 

TREATMENT

Medical Care

The main goals of treatment in angina pectoris are to relieve the symptoms, slow the progression of disease, and reduce the possibility of future events, especially MI and premature death.

• General measures
• • Smoking cessation results in a significant reduction of acute adverse effects on the heart and may reverse, or at least slow, atherosclerosis. Strongly encourage patients to quit smoking, and take an active role in helping them to achieve this goal.
  • Treat risk factors, including hypertension, diabetes mellitus, obesity, and hyperlipidemia.
  • Several clinical trials have shown that in patients with established coronary artery disease, reduction of low-density lipoprotein (LDL) level with a beta-hydroxy-beta-methylglutaryl coenzyme A reductase inhibitor (ie, statin) is associated with significant reductions in both mortality rate and major cardiac events.
  • • These benefits are present even in patients with mild-to-moderate elevations of LDL cholesterol level.
    • Recent trials with cholesterol-lowering agents have confirmed the benefits of the therapeutic LDL lowering in older persons.
    • Angiographic studies demonstrate that a reduction of the LDL level in patients with coronary artery disease could cause slowing of progression, stabilization, or even regression of coronary artery lesions.
    • A recent study demonstrates a significant reduction of symptomatic myocardial ischemia in patients with unstable angina or non–Q-wave infarction with the administration of a statin during the early acute phase.
    • In a study of 10,001 patients with stable coronary artery disease, an aggressive cholesterol-lowering approach with atorvastatin 80 mg daily (mean cholesterol level of 77 mg/dL) compared to a less-aggressive approach with atorvastatin 10 mg daily (mean cholesterol level of 101 mg/dL) resulted in a 2.2% absolute reduction and a 22% relative reduction in the occurrence of a first major cardiovascular event (defined as death from coronary heart disease; nonfatal, non–procedure-related myocardial infarction; resuscitation from cardiac arrest; or fatal or nonfatal stroke).¹ This occurred with a greater incidence of elevated aminotransferase levels with the aggressive cholesterol-lowering approach (1.2% vs 0.2%, p <0.001).
  • Based on several recent studies that have demonstrated the benefits of more aggressive LDL-lowering therapies in high-risk patients with coronary artery disease, the Committee of the National Cholesterol Education Program recently made the following modifications to the Adult Treatment Panel III (ATP III) guidelines.
  • • In high-risk patients, a serum LDL cholesterol level of less than 100 mg/dL is the goal.
    • In very high-risk patients, an LDL cholesterol level goal of less than 70 mg/dL is a therapeutic option. Patients in the category of very high risk are those with established coronary artery disease with one of the following: multiple major risk factors (especially diabetes), severe and poorly controlled risk factors (especially continued cigarette smoking), multiple risk factors of the metabolic syndrome (especially high triglyceride levels [³200 mg/dL] plus non-HDL cholesterol level [³130 mg/dL] with low HDL cholesterol level [<40 mg/dL]), and patients with acute coronary syndromes.
    • For moderately high-risk persons (2+ risk factors), the recommended LDL cholesterol level is less than130 mg/dL, but an LDL cholesterol level of 100 mg/dL is a therapeutic option.
  • Some triglyceride-rich lipoproteins, including partially degraded very LDL levels, are believed to be independent risk factors for coronary artery disease. In daily practice, non-HDL cholesterol level (ie, LDL + very LDL cholesterol [total cholesterol - HDL cholesterol]) is the most readily available measure of the total pool of these atherogenic lipoproteins. Thus, the ATP III has identified non-HDL cholesterol level as a secondary target of therapy in persons with high triglyceride levels (>200 mg/dL). The goal for non-HDL cholesterol level (for persons with serum triglyceride levels >200 mg/dL) is 30 mg/dL higher than the identified LDL cholesterol level goal.
  • Patients with established coronary disease and low HDL cholesterol levels are at high risk for recurrent events and should be targeted for aggressive nonpharmacological (ie, dietary modification, weight loss, physical exercise) and pharmacological treatment.
  • Several large epidemiologic studies demonstrated that HDL cholesterol levels are inversely related to cardiovascular risk. Thus, developing pharmaceutical agents to increase the HDL level has been an attractive target for prevention and treatment of CAD. Cholesteryl ester transfer protein (CETP) inhibitors have been shown to have the effect of increasing HDL cholesterol levels by blocking this CETP. Torcetrapib has been one of CETP agents that has been used in large randomized trials.
  • • Investigation of Lipid Level management using coronary UltraSound To assess Reduction of Atherosclerosis by CETP inhibition and HDL Elevation (ILLUSTRATE) was a randomized study that looked at the effect of torecetrapib in 1188 patients with CAD who underwent intravascular ultrasonography at baseline.² After treatment with atorvastatin to reduce levels of LDL cholesterol to less than 100 mg/dL, patients were randomly assigned to receive atorvastatin monotherapy or atorvastatin plus 60 mg of torcetrapib daily.
      Intravascular ultrasonography was repeated in 910 of these patients (77%) after 24 months of treatment to evaluate the disease progression. Compared with atorvastatin monotherapy, torcetrapib–atorvastatin therapy was associated with an impressive 61% relative increase in HDL levels and a 20% relative decrease in LDL levels resulting in an LDL to HDL ratio of less than 1.0 in this group of patients. Despite this favorable change in the HDL and LDL levels, among patients who underwent repeat intravascular ultrasonography, the percent atheroma volume between the 2 groups was not different. Torcetrapib did not result in significant decrease in the progression of coronary atherosclerosis, but it was associated with an increase in blood pressure.
    • Rating Atherosclerotic Disease change by Imaging with A New Cholesteryl-Ester-transfer protein inhibitor (RADIANCE) 2, a more recent trial, looked into the effect of torcetrapib on carotid atherosclerosis progression in patients with mixed dyslipidaemia.³ Although similar to the ILLUSTRATE trial, torcetrapib also substantially raised HDL levels and lowered LDL levels in this study; it did not affect the progression of carotid atherosclerosis. Similar to the ILLUSTRATE trial, torcetrapib also significantly increased systolic blood pressure.
    • Investigation of Lipid Level management to Understand its iMpact IN ATherosclerotic Events (ILLUMINATE), an international phase 3 study of 15,000 patients, was terminated early because it had already recorded 82 deaths in the patients taking torcetrapib-atorvastatin compared with 51 deaths in patients taking atorvastatin alone. In addition, the rates of MI, revascularization, angina, and heart failure were higher in the torcetrapib-atorvastatin arm. Due to the disappointing results of these studies, torcetrapib will not be developed further. Whether this failure represents a problem unique to torcetrapib or is common among the entire class of CETP inhibitors remains to be determined.
  • A recent study demonstrated that in patients with established coronary artery disease who have low HDL levels and low-risk LDL levels, drug therapy with medications that raise HDL levels and lower triglyceride levels but have no effect on LDL levels (eg, gemfibrozil) could significantly reduce the risk of major cardiac events.
  • Currently, the accepted approach to the management of patients with coronary artery disease and low HDL levels is as follows:
  • • In all persons with low HDL cholesterol levels, the primary target of therapy is to achieve the ATP III guideline LDL cholesterol level goals with diet, exercise, and drug therapy as needed.
    • After reaching the targeted LDL level goal, emphasis shifts to other issues. That is, in patients with low HDL cholesterol levels who have associated high triglyceride levels (>200 mg/dL), the secondary priority is to achieve the non-HDL cholesterol level goal of 30 mg/dL higher than the identified LDL cholesterol level goal. In patients with isolated low HDL cholesterol levels (triglycerides <200 mg/dL), drugs to raise the HDL cholesterol level (eg, gemfibrozil, nicotinic acid) can be considered.
  • Exercise training results in improvement of symptoms, increase in the threshold of ischemia, and improvement of patients' sense of well-being. However, before enrolling a patient in an exercise-training program, perform an exercise tolerance test to establish the safety of such a program.
  • Consider enteric-coated aspirin at a dose of 80-325 mg/d for all patients with stable angina who have no contraindications to its use. In patients in whom aspirin cannot be used because of allergy or gastrointestinal complications, consider clopidogrel.
  • Although early observational studies suggested a cardiovascular protective effect with the use of hormone replacement therapy, recent large randomized trials failed to demonstrate any benefit with hormone replacement therapy in the primary or secondary prevention of cardiovascular disease.
  • • In fact, these studies even demonstrated an increased risk of coronary artery disease and stroke in patients on hormone replacement therapy.
    • The Women's Health Initiative study demonstrated that the use of hormone replacement therapy for 1 year in 10,000 healthy postmenopausal women is associated with 7 more instances of coronary artery disease, 8 more strokes, 8 more pulmonary emboli, 8 more invasive breast cancers, 5 fewer hip fractures, and 6 fewer colorectal cancers.
    • Based on these data, the risks and benefits of hormone replacement therapy must be assessed on an individual basis for each patient.
• Sublingual nitroglycerin has been the mainstay of treatment for angina pectoris. Sublingual nitroglycerin can be used for acute relief of angina and prophylactically before activities that may precipitate angina. No evidence indicates that long-acting nitrates improve survival in patients with coronary artery disease.
• Beta-blockers are also used for symptomatic relief of angina and prevention of ischemic events. They work by reducing myocardial oxygen demand and by decreasing the heart rate and myocardial contractility. Beta-blockers have been shown to reduce the rates of mortality and morbidity following acute MI.
• Long-acting heart rate–slowing calcium channel blockers can be used to control anginal symptoms in patients with a contraindication to beta-blockers and in those in whom symptomatic relief of angina cannot be achieved with the use of beta-blockers, nitrates, or both. Avoid short-acting dihydropyridine calcium channel blockers because they have been shown to increase the risk of adverse cardiac events.
• Anginal symptoms in patients with Prinzmetal angina can be treated with calcium channel blockers with or without nitrates. In one study, supplemental vitamin E added to a calcium channel blocker significantly reduced anginal symptoms among such patients.
• In patients with syndrome X and hypertension, ACE inhibitors may normalize thallium perfusion defects and increase exercise capacity.

Surgical Care

• Revascularization therapy (ie, coronary revascularization) can be considered in patients with left main artery stenosis greater than 50%, 2- or 3-vessel disease and LV dysfunction (ejection fraction, <45%), poor prognostic signs during noninvasive studies, or severe symptoms despite maximum medical therapy. The 2 main coronary revascularization procedures are percutaneous transluminal coronary angioplasty, with or without coronary stenting, and coronary artery bypass grafting.
• Patients with 1- or 2-vessel disease and normal LV function who have anatomically suitable lesions are candidates for percutaneous transluminal coronary angioplasty and coronary stenting. Restenosis is the major complication, with symptomatic restenosis occurring in 20-25% of patients. Restenosis mostly occurs during the first 6 months after the procedure and can be managed by repeat angioplasty. Several trials have demonstrated that the use of drug-eluting stents (eg, sirolimus-eluting stents, paclitaxel-coated stents) can remarkably reduce the rate of in-stent restenosis. With the introduction of these drug-coated stents, patients with multivessel coronary artery disease are more frequently treated with percutaneous revascularization as opposed to the surgical revascularization.
  More recently, some concerns have arisen that instead of improving the long-term prognosis, drug-eluting stents might actually worsen it. In addition, stent thrombosis is a major concern with the use of drug-eluting stents. A meta-analysis of individual data on 4958 patients enrolled in 14 randomized trials comparing sirolimus-eluting stents with bare-metal stents looked at the long-term effect of these stents.⁴ The mean follow-up interval was 12.1-58.9 months. The primary end point was death from any cause. The secondary end points were stent thrombosis, the composite end point of death or myocardial infarction, and the composite of death, MI, or a revascularization. The overall risk of death and the combined risk of death or MI were not significantly different for patients receiving sirolimus-eluting stents versus bare-metal stents. A sustained reduction in the need for revascularization occurred after the use of sirolimus-eluting stents compared with bare-metal stents. The overall risk ofstentthrombosis with sirolimus-eluting stents was not significantly higher than bare-metal stents. However, evidence showed an increase in the risk of stent thrombosis associated with sirolimus-eluting stents after the first year.
• Patients with single-vessel disease and normal ventricular function treated with percutaneous transluminal coronary angioplasty show improved exercise tolerance and fewer episodes of angina compared with those who receive medical treatment. However, no difference in the frequency of MI or death has been shown between these two groups.
• The Clinical Outcomes Utilizing Revascularization and AGgressive Drug Evaluation (COURAGE) trial looked at the benefits of PCI as an initial management strategy in patients with stable CAD. This trial was a randomized and involved 2287 patients who had objective evidence of myocardial ischemia and significant CAD.⁵ Of these, 1149 patients were randomized to undergo PCI with optimal medical therapy (PCI group) and 1138 were to receive optimal medical therapy alone (medical-therapy group). They were observed for 2.5-7 years (median, 4.6 y). During the follow-up, no difference was reported in the primary outcome of death from any cause and nonfatal MI between the PCI group and the medical-therapy group. In addition, no significant differences were noted between the 2 groups in the secondary end points of the composite of death, MI, and stroke; hospitalization for acute coronary syndrome; or MI.
• Patients with significant left main coronary artery disease, 2- or 3-vessel disease and LV dysfunction, diabetes mellitus, or lesions anatomically unsuitable for percutaneous transluminal coronary angioplasty have better results with coronary artery bypass grafting. The overall operative mortality rate for coronary artery bypass grafting is approximately 1.3%. The rate of graft patency 10 years after surgery is less than 50% for vein grafting, although more than 90% of grafts using internal mammary arteries are patent at 10 years. In recent years, interest has increased regarding surgery without cardiopulmonary bypass (ie, off-pump) in an attempt to avoid the morbidity associated with cardiopulmonary bypass. A recent randomized study demonstrated that off-pump coronary surgery was as safe as on-pump surgery and caused less myocardial damage. However, the graft-patency rate was lower at 3 months in the off-pump group than in the on-pump group.
• Recently, laser transmyocardial revascularization has been used as an experimental therapy for the treatment of severe, chronic, stable angina refractory to medical or other therapies. This technique has been performed with either an epicardial surgical technique or by a percutaneous approach. In both approaches, a series of transmural endomyocardial channels are created to improve myocardial perfusion. The surgical transmyocardial revascularization technique has been associated with symptomatic relief for end-stage chronic angina in the short term. However, no published data address the long-term efficacy of surgical transmyocardial revascularization. Nonetheless, this technique appears to provide at least symptomatic relief for end-stage chronic angina in the short term.

Diet

A diet low in saturated fat and dietary cholesterol is the mainstay of the Step I and Step II diet from the American Heart Association.

Activity

The level of activity that aggravates anginal symptoms is different for each patient. However, most patients with stable angina can avoid symptoms during daily activities simply by reducing the speed of activity.

MEDICATION

The goals of pharmacotherapy are to reduce morbidity and to prevent complications.

Drug Category: Antiplatelet agents

Prevent thrombus formation by inhibiting platelet aggregation. Aspirin is proven beneficial in primary and secondary prevention of coronary artery disease. In patients with aspirin intolerance, use clopidogrel. Clopidogrel is also used in combination with aspirin after coronary stent placement. Recently, clopidogrel use in addition to aspirin has been shown to be significantly superior to aspirin alone in patients with acute coronary syndrome without ST-segment elevation MI.

Drug Name
Aspirin (Bayer, Empirin, Anacin)

Description
Prevents platelet aggregation by irreversible cyclooxygenase inhibition with subsequent suppression of thromboxane A2. Antiplatelet effect can last as long as 7 d.

Adult Dose
81-325 mg PO qd

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; liver damage; hypoprothrombinemia; vitamin K deficiency; bleeding disorders; asthma
Because of association with Reye syndrome, do not use in children ( <16 y) with flu

Interactions
Antacids and urinary alkalinizers may decrease effects; corticosteroids decrease salicylate serum levels; anticoagulants may cause additive hypoprothrombinemic effects and increased bleeding time; may antagonize uricosuric effects of probenecid and increase toxicity of phenytoin and valproic acid; doses > 2 g/d may potentiate glucose-lowering effect of sulfonylurea drugs

Pregnancy
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus

Precautions
May cause transient decrease in renal function and aggravate chronic kidney disease; avoid use in patients with severe anemia, history of blood coagulation defects, or taking anticoagulants; adverse effects include prolonged bleeding time, rhinitis, asthma, urticaria, and exacerbation of gout; monitor BP, BUN, and uric acid level; consider discontinuing 7 d before surgery

Drug Name
Clopidogrel (Plavix)

Description
Selectively inhibits ADP binding to platelet receptor and subsequent ADP-mediated activation of GPIIb/IIIa complex, thereby inhibiting platelet aggregation. Consider in patients with contraindication to aspirin.

Adult Dose
75 mg PO qd

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; active pathological bleeding

Interactions
Naproxen associated with increased occult GI blood loss; prolongs bleeding time; safety of coadministration with warfarin not established

Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions
Caution in patients at increased risk of bleeding from trauma, surgery, or other pathological conditions; caution in patients with lesions with propensity to bleed (eg, ulcers); adverse effects include rash, diarrhea, purpura, GI ulcers, neutropenia, and rare cases of agranulocytosis; consider discontinuing 7 d before surgery

Drug Category: Beta-adrenergic blocking agents

Work by competing with endogenous catecholamines for beta-adrenergic receptors. Reduce myocardial oxygen consumption via several effects, including decrease in resting and exercise heart rates and reductions in myocardial contractility and afterload. Classified as nonselective, beta-1 selective, and having intrinsic sympathomimetic effects.

Drug Name
Metoprolol (Lopressor, Toprol XL)

Description
Selective beta1-adrenergic receptor blocker that decreases automaticity of contractions. Is lipophilic and penetrates CNS.

Adult Dose
50-200 mg PO bid

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; uncompensated CHF; bradycardia; asthma; cardiogenic shock; AV conduction abnormalities

Interactions
Aluminum salts, barbiturates, NSAIDs, penicillins, calcium salts, cholestyramine, and rifampin may decrease bioavailability and plasma levels, possibly resulting in decreased pharmacologic effects; sparfloxacin, phenothiazines, astemizole, calcium channel blockers, quinidine, flecainide, and contraceptives may increase toxicity; may increase toxicity of digoxin, flecainide, clonidine, epinephrine, nifedipine, prazosin, verapamil, and lidocaine

Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions
Beta-adrenergic blockade may mask signs and symptoms of acute hypoglycemia and may decrease clinical signs of hyperthyroidism; abrupt withdrawal may exacerbate symptoms of hyperthyroidism, including thyroid storm; monitor patient closely and withdraw drug slowly; during IV administration, carefully monitor BP, heart rate, and ECG; adverse effects include hypotension, decreased libido, impotence, lethargy, depression, and decreased HDL; may cause less bronchial tree and arterial smooth muscle constriction

Drug Name
Atenolol (Tenormin)

Description
Selectively blocks beta-1 receptors with little or no effect on beta-2 receptors. Is hydrophilic and does not penetrate CNS.

Adult Dose
50-200 mg PO qd

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; CHF; pulmonary edema; cardiogenic shock; AV conduction abnormalities; heart block (without pacemaker)

Interactions
Aluminum salts, barbiturates, calcium salts, cholestyramine, NSAIDs, penicillins, and rifampin may decrease effects; haloperidol, hydralazine, loop diuretics, and MAOIs may increase toxicity

Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions
Beta-adrenergic blockade may hide symptoms of acute hypoglycemia and mask signs of hyperthyroidism; abrupt withdrawal may exacerbate symptoms of hyperthyroidism and cause thyroid storm; monitor patients closely and withdraw drug slowly; adverse effects include bradycardia, hypotension, decreased libido, impotence, and decreased HDL; beta1-selective blockers may cause less bronchial tree and arterial smooth muscle constriction; titrate dose carefully to level of patient tolerance and effectiveness

Drug Name
Propranolol (Inderal)

Description
Nonselective beta-blocker that is lipophilic (penetrates CNS). Although generally short-acting agent, long-acting preparations also available.

Adult Dose
IR: 40-160 mg PO bid
SR: 60-320 mg PO qd

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; history of bronchospasm; uncompensated CHF; bradycardia; cardiogenic shock; AV conduction abnormalities

Interactions
Aluminum salts, barbiturates, NSAIDs, penicillins, calcium salts, cholestyramine, and rifampin may decrease effects; calcium channel blockers, cimetidine, loop diuretics, and MAOIs may increase toxicity; may increase toxicity of hydralazine, haloperidol, benzodiazepines, and phenothiazines

Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions
Beta-adrenergic blockade may mask signs of acute hypoglycemia and hyperthyroidism; abrupt withdrawal may exacerbate symptoms of hyperthyroidism, including thyroid storm; withdraw drug slowly and monitor closely; adverse effects include bronchial constriction, Raynaud phenomenon, hypotension, decreased libido, impotence, lethargy, depression, and decreased HDL; caution in Wolff-Parkinson-White syndrome and renal or hepatic dysfunction

Drug Category: Calcium channel blockers

Reduce transmembrane flux of calcium via calcium channels. Cause smooth muscle relaxation, resulting in peripheral arterial vasodilation and afterload reduction. Indicated when symptoms persist despite treatment with beta-blockers or when beta-blockers are contraindicated. Also indicated in patients with Prinzmetal angina with or without nitrates.

Drug Name
Amlodipine (Norvasc)

Description
During depolarization, inhibits calcium ions from entering slow channels and voltage-sensitive areas of vascular smooth muscle and myocardium.

Adult Dose
5-10 mg PO qd

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; severe CHF; sick sinus syndrome; second- or third-degree AV block; hypotension (<90 mm Hg systolic)

Interactions
Fentanyl may increase hypotensive effects; may increase cyclosporine levels; H2 blockers (eg, cimetidine) may increase toxic effects

Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions
Severe aortic stenosis, CHF, hepatic dysfunction; adverse effects include headache, edema, flushing, palpitation, drowsiness, and fatigue

Drug Name
Diltiazem (Cardizem CD, Dilacor)

Description
During depolarization, inhibits calcium ions from entering slow channels and voltage-sensitive areas of vascular smooth muscle and myocardium.

Adult Dose
IR: 120-360 mg PO divided tid/qid
SR: 120-480 mg PO qd

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; severe CHF; sick sinus syndrome; second- or third-degree AV block; hypotension (<90 mm Hg systolic)

Interactions
May increase carbamazepine, digoxin, cyclosporine, and theophylline levels; when administered with amiodarone, may cause bradycardia and decrease in cardiac output; when given with beta-blockers may increase cardiac depression; cimetidine may increase levels

Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions
Caution in impaired renal or hepatic function; may increase LFT levels, and hepatic injury may occur; adverse effects include constipation, AV conduction block, worsening of heart failure, peripheral edema, bradycardia, and AV dissociation

Drug Name
Verapamil (Calan, Covera)

Description
During depolarization, inhibits calcium ion from entering slow channels or voltage-sensitive areas of vascular smooth muscle and myocardium.

Adult Dose
IR: 80-120 mg PO tid/qid
SR: 120-240 mg PO qd/bid

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; severe CHF; sick sinus syndrome; second- or third-degree AV block; hypotension (<90 mm Hg systolic)

Interactions
May increase carbamazepine, digoxin, theophylline, and cyclosporine levels; amiodarone can cause bradycardia and decrease in cardiac output; when administered concurrently with beta-blockers may increase cardiac depression; cimetidine may increase levels

Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions
Hepatocellular injury may occur; transient elevations of transaminases with and without concomitant elevations in alkaline phosphatase and bilirubin have occurred (elevations have been transient and may disappear with continued treatment); monitor liver function periodically; adverse effects include constipation, AV dissociation, worsening heart failure, bradycardia, negative inotropism, and hypotension

Drug Category: Short-acting nitroglycerins

Suitable for immediate relief of exertional or rest angina. Can also be used for prophylaxis several minutes before planned exercise to avoid angina. Reduce myocardial oxygen demand by reduction of LV and arterial pressure, primarily by reducing preload.

Drug Name
Nitroglycerin (Nitrostat, Nitro-bid, Nitrol)

Description
Causes relaxation of vascular smooth muscle by stimulating intracellular cyclic GMP production. Result is decrease in BP.

Adult Dose
0.3-0.6 mg SL prn
0.4 mg metered-dose spray PO prn
0.1-0.8 mg/h patch TD qd

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; severe anemia; shock; postural hypotension; head trauma; closed-angle glaucoma; cerebral hemorrhage; hypertrophic obstructive cardiomyopathy

Interactions
Concurrent sildenafil (Viagra) may cause severe hypotension and death; aspirin may increase serum concentrations; calcium channel blockers may cause markedly symptomatic orthostatic hypotension (dose adjustment of either agent may be necessary)

Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions
Caution in coronary artery disease and low systolic BP; adverse effects include hypotension, flushing, headache, light-headedness, and tolerance (8- to 12-h nitrate-free interval is most effective method to prevent development of tolerance); high IV doses may cause methemoglobinemia, heparin resistance, and ethanol intoxication; ischemia may worsen upon withdrawal

Drug Category: Long-acting nitroglycerins

Reduce LV preload and afterload by venous and arterial dilation, which subsequently reduces myocardial oxygen consumption and relieves angina. Also cause dilation of epicardial coronary arteries, which is beneficial in patients with coronary spasm. In addition, nitroglycerin has antithrombotic and antiplatelet effects in patients with angina pectoris. No evidence suggests that nitrates improve survival or slow progression of coronary artery disease.

Drug Name
Isosorbide (Isordil, ISMO)

Description
Relaxes vascular smooth muscle by stimulating intracellular cyclic GMP. Decreases LV pressure (ie, preload) and arterial resistance (ie, afterload). Reduces cardiac oxygen demand by decreasing LV pressure and dilating arteries.

Adult Dose
Isosorbide dinitrate:
2.5-10 mg SL prn IR
10-30 mg PO bid/tid SR
80-120 mg PO qd IR
Isosorbide mononitrate:
10-20 mg PO bid SR
30-120 mg PO qd

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; severe anemia; closed-angle glaucoma; postural hypotension; head trauma; cerebral hemorrhage

Interactions
Alcohol may cause severe hypotension and cardiovascular collapse; aspirin may increase serum concentrations and actions; calcium channel blockers may increase symptomatic orthostatic hypotension (adjust dose of either agent); may decrease effects of heparin

Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions
Tolerance to vascular and antianginal effects of nitrates may develop; minimize tolerance by using smallest effective dose or pulse therapy (intermittent dosing) or by alternating with other coronary vasodilators (take last daily dose of short-acting agent no later than 7 pm); caution when administering to patients with glaucoma

Drug Category: Angiotensin-converting enzyme inhibitors

Recently shown to reduce rates of death, MI, stroke, and need for revascularization procedures in patients with coronary artery disease or diabetes mellitus and at least one other cardiovascular risk factor, irrespective of the presence of hypertension or heart failure.

Drug Name
Ramipril (Altace)

Description
Prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in lower aldosterone secretion.

Adult Dose
2.5-5 mg PO qd; not to exceed 20 mg/d

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; history of angioedema

Interactions
May increase digoxin, lithium, and allopurinol levels; probenecid may increase levels; coadministration with diuretics increases hypotensive effects; NSAIDs may reduce hypotensive effects

Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus

Precautions
Adverse effects include persistent cough, angioedema, hypotension, and prerenal azotemia; caution in renal impairment, valvular stenosis, or severe CHF

Drug Category: Anti-ischemic agents, miscellaneous

Ranolazine elicits action unlike beta-blockers, calcium antagonists, or nitrates. It does not affect hemodynamics or contractile and conduction parameters.

Drug Name
Ranolazine (Ranexa)

Description
Cardioselective anti-ischemic agent (piperazine derivative) that partially inhibits fatty acid oxidation. Also inhibits late sodium current into myocardial cells and prolongs QTc interval. Indicated for chronic angina unresponsive to other antianginal treatments. Used in combination with amlodipine, beta-blockers, or nitrates. Unlike beta-blockers, calcium channel blockers, and nitrates, does not reduce blood pressure or heart rate. Effect on angina rate or exercise tolerance appears to be smaller in women than in men. Absorption is highly variable but unaffected by food.

Adult Dose
500 mg PO bid initially; if necessary, may increase to 1000 mg PO bid

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; preexisting QT prolongation; hepatic impairment (Child-Pugh class A [mild], B [moderate], or C [severe]); QT-prolonging drugs (see Interactions); potent or moderate CYP4503A inhibitors (eg, ketoconazole, diltiazem)

Interactions
CYP4503A and P-gp substrate; potent CYP3A inhibitors (eg, ketoconazole at 200 mg bid) increase levels approximately 3.2-fold, moderate CYP3A inhibitors (eg, diltiazem at 180-360 mg/d) increase levels approximately 1.8- to 2.3-fold, and verapamil (a CYP3A and P-gp inhibitor) increases levels approximately 2-fold; caution with other P-gp inhibitors (eg, ritonavir, cyclosporine); toxicity may occur when coadministered with other drugs that increase QTc interval (eg, class I and III antiarrhythmic agents, certain macrolide and quinolone antibiotics, phenothiazines, TCAs)
Inhibits CYP4503A, CYP 4502D6, and P-gp; may increase plasma levels of digoxin, simvastatin, dextromethorphan, TCAs, and antipsychotics

Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions
Causes dose-related QTc-interval prolongation (obtain baseline and follow-up ECGs to monitor for torsades de pointes and potential for sudden death; mild and moderate hepatic impairment increases QTc interval compared with normal hepatic function at same plasma level; increases blood pressure by approximately 15 mm Hg in persons with severe renal impairment; common adverse effects include dizziness, headache, constipation, and nausea

 

FOLLOW-UP

Deterrence/Prevention:

• Coronary atherosclerosis is the main preventable cause of mortality in the United States. A rigorous effort to address correctable risk factors is the mainstay of preventive cardiovascular medicine.
• Smoking cessation is the single most effective preventive intervention to reduce coronary atherosclerosis prevalence. It has been associated with a coronary artery disease reduction of 7-47% in primary prevention settings.
• Aggressive treatment of diabetes mellitus, hypertension, LV hypertrophy, hyperlipidemia, and obesity has an important role in the prevention of coronary artery disease.
• The most important recent development in coronary atherosclerosis risk modification is the introduction of inhibitors of beta-hydroxy-beta-methylglutaryl coenzyme A reductase. Reductions of total and LDL cholesterol levels by 25% and 35%, respectively, can achieve a similar reduction in rates of total and coronary mortality, MI, and need for coronary revascularization.

Complications:

• Complications of angina pectoris include unstable angina, MI, and death.

Prognosis:

• Important prognostic indicators in patients with angina pectoris include LV function, severity and location of atherosclerotic lesions, and response of symptoms to medical treatment.
• • LV function is the strongest predictor of long-term survival. Elevated LV end-diastolic pressure and volume along with reduced LV ejection fraction ( <40%) are poor prognostic signs.
  • Critical lesions of left main and proximal left anterior descending coronary arteries are associated with a greater risk. Mortality rates are also directly associated with the number of epicardial arteries involved.
  • Unstable angina, recent MI, or both is a sign of atherosclerotic plaque instability, which is a strong predictor of increased risk of short-term coronary events.
• A number of signs during noninvasive testing are predictive of a higher risk of coronary events, including ST-segment depression of more than 2 mm at a low workload, ST-segment depression that persists for more than 5 minutes after termination of exercise, and failure of blood pressure to rise or an actual drop in blood pressure.
• Patients who continue to smoke after an MI have a 22-47% increased risk of reinfarction and death.
• In general, Prinzmetal angina and syndrome X are associated with excellent long-term prognoses.

Patient Education:

• Educating patients about the benefits of smoking cessation, a low-cholesterol diet, physical activity, and periodic screening for diabetes mellitus and hypertension is the prime component of a long-term management plan.
• For excellent patient education resources, visit eMedicine's Circulatory Problems Center, Cholesterol Center, Heart Center, and Statins Center. Also, see eMedicine's patient education articles Angina Pectoris, High Cholesterol, Understanding Your Cholesterol Level, Lifestyle Cholesterol Management, Understanding Cholesterol-Lowering Medications, Chest Pain, Coronary Heart Disease, and Heart Attack.

REFERENCES

http://www.emedicine.com/med/topic133.htm

Heart Failure

Article Last Updated: Jan 2, 2006

AUTHOR AND EDITOR INFORMATION

Michael E Zevitz, MD, Assistant Professor of Medicine, Finch University of the Health Sciences, The Chicago Medical School; Consulting Staff, Private Practice
Michael E Zevitz is a member of the following medical societies: American College of Cardiology, American College of Physicians, American Medical Association, and Michigan State Medical Society
Editors: George A Stouffer III, MD, Henry A Foscue Distinguished Professor of Medicine and Cardiology, Director of Interventional Cardiology, Cardiac Catheterization Laboratory, Vice Chief, Cardiology for Clinical Affairs, Director UNC Heart Center, Division of Cardiology, University of North Carolina Medical Center; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Marschall S Runge, MD, PhD, Marion Covington Distinguished Professor of Medicine, Vice Dean for Clinical Affairs, Chairman, Department of Medicine, University of North Carolina at Chapel Hill School of Medicine; Amer Suleman, MD, Consultant in Electrophysiology and Cardiovascular Medicine, Department of Internal Medicine, Division of Cardiology, Medical City Dallas Hospital; Leonard Ganz, MD, Associate Professor of Medicine, Temple University School of Medicine; Cardiac Electrophysiologist, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Cent, West Penn Hospital

 

INTRODUCTION

Background

Heart failure is the pathophysiologic state in which the heart, via an abnormality of cardiac function (detectable or not), fails to pump blood at a rate commensurate with the requirements of the metabolizing tissues and/or pumps only from an abnormally elevated diastolic filling pressure.

Heart failure may be caused by myocardial failure but may also occur in the presence of near-normal cardiac function under conditions of high demand. Heart failure always causes circulatory failure, but the converse is not necessarily the case because various noncardiac conditions (eg, hypovolemic shock, septic shock) can produce circulatory failure in the presence of normal, modestly impaired, or even supranormal cardiac function.

In terms of incidence, prevalence, morbidity, and mortality, the epidemiologic magnitude of congestive heart failure (CHF) is staggering. In the United States, the estimated annual cost of heart failure is $60 billion; the estimated annual cost of inpatient care of patients with CHF is $23 billion. Approximately 1 million US hospital admissions per year are attributable to a primary diagnosis of acutely decompensated heart failure. For additional resources, please visit Heart Failure Resource Center.

Pathophysiology

Inadequate adaptation of the cardiac myocytes to increased wall stress in order to maintain adequate cardiac output following myocardial injury (whether of acute onset or over several months to years, whether a primary disturbance in myocardial contractility or an excessive hemodynamic burden placed on the ventricle, or both), is the inciting event in CHF.

Most important among these adaptations are the (1) Frank-Starling mechanism, in which an increased preload helps to sustain cardiac performance; (2) myocardial hypertrophy with or without cardiac chamber dilatation, in which the mass of contractile tissue is augmented; and (3) activation of neurohumoral systems, especially the release of norepinephrine (NE) by adrenergic cardiac nerves, which augments myocardial contractility and the activation of the renin-angiotensin-aldosterone system (RAAS) and other neurohumoral adjustments that act to maintain arterial pressure and perfusion of vital organs. In acute heart failure, the finite adaptive mechanisms that may be adequate to maintain the overall contractile performance of the heart at relatively normal levels become maladaptive when trying to sustain adequate cardiac performance.

The primary myocardial response to chronic increased wall stress includes myocyte hypertrophy and remodeling, usually of the eccentric type. The reduction of cardiac output following myocardial injury sets into motion a cascade of hemodynamic and neurohormonal derangements that provoke activation of neuroendocrine systems, most notably the above-mentioned adrenergic systems and RAAS. The release of epinephrine (E) and NE, along with the vasoactive substances endothelin-1 (ET-1) and vasopressin (V), causes vasoconstriction, which increases afterload, and, via an increase in cyclic adenosine monophosphate (cAMP), causes an increase in cytosolic calcium entry. The increased calcium entry into the myocytes augments myocardial contractility and impairs myocardial relaxation (lusitropy).

The calcium overload may also induce arrhythmias and lead to sudden death. The increase in afterload and myocardial contractility (known as inotropy) and the impairment in myocardial lusitropy lead to an increase in myocardial energy expenditure and a further decrease in cardiac output. The increase in myocardial energy expenditure leads to myocardial cell death, resulting in heart failure and further reduction in cardiac output, thus starting an accelerating cycle of further increased neurohumoral stimulation and further adverse hemodynamic and myocardial responses as described above.

In addition, the activation of the RAAS leads to salt and water retention, resulting in increased preload and further increases in myocardial energy expenditure. Increases in renin, mediated by decreased stretch of the glomerular afferent arteriole, reduced delivery of chloride to the macula densa, and increased beta1-adrenergic activity as a response to decreased cardiac output, results in an increase in angiotensin II (Ang II) levels and, in turn, aldosterone levels. This results in stimulation of release of aldosterone. Ang II, along with ET-1, is crucial in maintaining effective intravascular homeostasis mediated by vasoconstriction and aldosterone-induced salt and water retention.

Some evidence indicates that local cardiac Ang II production, with a resultant decrease in lusitropy, increase in inotropy, and increase in afterload, leads to increased myocardial energy expenditure. In this fashion, Ang II has similar actions to NE in CHF.

Ang II also mediates myocardial cellular hypertrophy and may promote progressive loss of myocardial function. The neurohumoral factors above lead to myocyte hypertrophy and interstitial fibrosis, resulting in increased myocardial volume and increased myocardial mass, as well as myocyte loss. The increase in myocardial volume results in myocyte slippage, which also results in further increases in myocardial volume and mass. These features, namely the increased myocardial volume and mass, along with myocyte loss, are the hallmark of myocardial remodeling. This remodeling process leads to early adaptive mechanisms, such as augmentation of stroke volume (Starling mechanism) and decreased wall stress (Laplace mechanism), and later, maladaptive mechanisms such as increased myocardial oxygen demand, myocardial ischemia, impaired contractility, and arrhythmogenesis.

As heart failure advances and/or becomes progressively decompensated, there is a relative decline in the counterregulatory effects of endogenous vasodilators, including nitric oxide (NO), prostaglandins (PGs), bradykinin (BK), atrial natriuretic peptide (ANP), and B-type natriuretic peptide (BNP). This occurs simultaneously with the increase in vasoconstrictor substances from the RAAS and adrenergic systems. This fosters further increases in vasoconstriction and thus preload and afterload, leading to cellular proliferation, adverse myocardial remodeling, and antinatriuresis with total body fluid excess and worsening CHF symptoms.

Both systolic and diastolic heart failure result in a decrease in stroke volume. This leads to activation of peripheral and central baroreflexes and chemoreflexes that are capable of eliciting marked increases in sympathetic nerve traffic. While there are commonalities in the neurohormonal responses to decreased stroke volume, the neurohormone-mediated events that follow have been most clearly elucidated for individuals with systolic heart failure. The ensuing elevation in plasma NE directly correlates with the degree of cardiac dysfunction and has significant prognostic implications. NE, while being directly toxic to cardiac myocytes, is also responsible for a variety of signal-transduction abnormalities, such as down-regulation of beta1-adrenergic receptors, uncoupling of beta2-adrenergic receptors, and increased activity of inhibitory G-protein. Changes in beta1-adrenergic receptors result in overexpression and promote myocardial hypertrophy.

ANP and BNP are endogenously generated peptides activated in response to atrial and ventricular volume/pressure expansion. ANP and BNP are released from the atria and ventricles, respectively, and both promote vasodilation and natriuresis. Their hemodynamic effects are mediated by decreases in ventricular filling pressures, owing to reductions in cardiac preload and afterload. BNP, in particular, produces selective afferent arteriolar vasodilation and inhibits sodium reabsorption in the proximal convoluted tubule. BNP inhibits renin and aldosterone release and, possibly, adrenergic activation as well. Both ANP and BNP are elevated in chronic heart failure. BNP, in particular, has potentially important diagnostic, therapeutic, and prognostic implications.

Other vasoactive systems that play a role in the pathogenesis of CHF include the ET receptor system, adenosine receptor system, V, and tumor necrosis factor-alpha (TNF-alpha). ET, a substance produced by the vascular endothelium, may contribute to the regulation of myocardial function, vascular tone, and peripheral resistance in CHF. Elevated levels of ET-1 closely correlate with the severity of heart failure. ET-1 is a potent vasoconstrictor and has exaggerated vasoconstrictor effects in the renal vasculature, reducing renal plasma blood flow, glomerular filtration rate (GFR), and sodium excretion. TNF-alpha has been implicated in response to various infectious and inflammatory conditions. Elevations in TNF-alpha levels have been consistently observed in CHF and seem to correlate with the degree of myocardial dysfunction. Experimental studies suggest that local production of TNF-alpha may have toxic effects on the myocardium, thus worsening myocardial systolic and diastolic function.

Thus, in individuals with systolic dysfunction, the neurohormonal responses to decreased stroke volume result in temporary improvement in systolic blood pressure and tissue perfusion. However, in all circumstances, the existing data support the notion that these neurohormonal responses accelerate the downward spiral of myocardial dysfunction in the long term.

In diastolic heart failure, the same pathophysiologic processes to decreased cardiac output that occur in systolic heart failure also occur, but they do so in response to a different set of hemodynamic and circulatory environmental factors that depress cardiac output.

In diastolic heart failure, altered relaxation of the ventricle (due to delayed calcium uptake by the myocyte sarcoplasmic reticulum and delayed calcium efflux from the myocyte) occurs in response to an increase in ventricular afterload (pressure overload). The impaired relaxation of the ventricle leads to impaired diastolic filling of the left ventricle (LV).

An increase in LV chamber stiffness occurs secondary to any one of the following 3 mechanisms or to a combination thereof: (1) a rise in filling pressure (ie, movement of the ventricle up along its pressure-volume curve to a steeper portion, as may occur in conditions such as volume overload secondary to acute valvular regurgitation or acute LV failure due to myocarditis); (2) a shift to a steeper ventricular pressure-volume curve, occurring most commonly as a result of not only increased ventricular mass and wall thickness, as observed in (a) aortic stenosis and (b) long-standing hypertension, but also in (c) infiltrative disorders such as amyloidosis, (d) endomyocardial fibrosis, and (e) myocardial ischemia; and (3) a parallel upward displacement of the diastolic pressure-volume curve, generally referred to as a decrease in ventricular distensibility, usually caused by extrinsic compression of the ventricles.

Whereas volume overload, as observed in chronic aortic and/or mitral valvular regurgitant disease, shifts the entire diastolic pressure-volume curve to the right, indicating increased chamber stiffness, pressure overload that leads to concentric LV hypertrophy (as occurs in aortic stenosis, hypertension, and hypertrophic cardiomyopathy) shifts the diastolic pressure-volume curve to the left along its volume axis so that at any diastolic volume ventricular diastolic pressure is abnormally elevated, although chamber stiffness may or may not be altered. Increases in diastolic pressure lead to increased myocardial energy expenditure, remodeling of the ventricle, increased myocardial oxygen demand, myocardial ischemia, and eventual progression of the maladaptive mechanisms of the heart that lead to decompensated heart failure.

Frequency

United States

CHF is the fastest-growing clinical cardiac disease entity in the United States, affecting 2% of the population. Nearly 1 million hospital admissions for acute decompensated CHF occur in the United States yearly, almost double the number seen 15 years ago. The rehospitalization rates during the 6 months following discharge are as much as 50%. Nearly 2% of all hospital admissions in the United States are for decompensated CHF, and heart failure is the most frequent cause of hospitalization in patients older than 65 years. The average duration of hospitalization is about 6 days. An estimated $23 billion are spent on inpatient management of CHF every year, and another $40 billion are spent in the outpatient setting on patients with compensated or mildly decompensated heart failure every year. Despite aggressive therapies, hospital admissions for CHF continue to increase, reflecting the prevalence of this malady.

International

CHF is a worldwide problem, but few accurate financial data are available. As discussed elsewhere, the most common cause of CHF in industrialized countries is ischemic cardiomyopathy. Other causes, including Chagas disease, assume a more important role in underdeveloped countries than in the United States.

Mortality/Morbidity

Despite recent advances in the management of patients with heart failure, morbidity and mortality rates remain high, with an estimated 5-year mortality rate of 50%.

• Assigning figures for inpatient mortality rates is difficult because the causes and the severity of heart failure vary considerably. The most recent estimates of inpatient mortality rates indicate that death occurs in up to 5-20% of patients.
• Hypoxemia that occurs in decompensated CHF, which may be severe, may result in myocardial ischemia or infarction.
• Respiratory failure with hypercapnic respiratory acidosis may occur in severe decompensated CHF, requiring mechanical ventilation if medical therapy is delayed or unsuccessful. Endotracheal intubation and mechanical ventilation are associated with their own risks, including aspiration (during the intubation process), mucosal trauma (more common with nasotracheal intubation than orotracheal intubation), and barotrauma.
• In patients with CHF, the risk of cardiac sudden death from ventricular tachycardia (VT) or ventricular fibrillation is considerable, and the degree of risk is correlated with the degree of decompensation and the degree of LV dysfunction. Recognition of the role of ventricular arrhythmias and advances in their treatment have resulted in decreased mortality rates in individuals with CHF.
• Progressive renal insufficiency due to decreased renal blood flow and GFR are common in patients with long-standing CHF.
• Liver dysfunction due to passive hepatic congestion is particularly common in patients with right-sided CHF with elevated right ventricular (RV) pressure that is transmitted back into the portal vein.
  • Mild jaundice, mild abnormalities in coagulation, and derangements in liver metabolism of medications, some of which are used in the treatment of heart failure, may result from this liver dysfunction.
  • Toxic levels of medications such as warfarin, theophylline, phenytoin, and digoxin can result from delayed liver metabolic clearance of these drugs in the presence of decompensated CHF, thereby leading to potentially fatal bleeding, cardiac dysrhythmias, and neurologic abnormalities.

Race

The incidence and prevalence of CHF are higher in African Americans, Hispanic persons, Native Americans, and recent immigrants from nonindustrialized nations, Russia, and the former Soviet republics.

• The higher prevalence of CHF in African Americans, Hispanic persons, and Native Americans is directly related to the higher incidence and prevalence of hypertension and diabetes. This problem is particularly exacerbated by a lack of access to health care and to substandard preventive health care of the most indigent of these and other groups; many persons within these groups are without adequate health insurance coverage.
• The higher incidence and prevalence of CHF among recent immigrants from nonindustrialized nations is largely due to a lack of prior preventive health care and to a lack of treatment or to substandard treatment for common conditions such as hypertension, diabetes, rheumatic fever, and ischemic heart disease.

Sex

Men and women have equivalent incidence and prevalence of CHF. CHF in women tends to occur later in life compared to men.

Age

The prevalence of CHF increases with age, being most common in individuals older than 65 years. In the United States, CHF is the most common reason for hospital admission in patients older than 65 years. Nonetheless, CHF can occur at any age, depending on the cause.

 

CLINICAL

History

Breathlessness, a cardinal sign of LV failure, may manifest with progressively increasing severity as (1) exertional dyspnea, (2) orthopnea, (3) paroxysmal nocturnal dyspnea, (4) dyspnea at rest, and (5) acute pulmonary edema. The New York Heart Association (NYHA) Classification of Heart Failure (see Staging), which varies slightly from the above categorization of CHF symptoms, is widely used in practice and in clinical studies to quantify clinical assessment of CHF.

• Exertional dyspnea
• • The principal difference between exertional dyspnea in subjects who are healthy and exertional dyspnea in patients with heart failure is the degree of activity necessary to induce the symptom. As heart failure first develops, exertional dyspnea may simply appear to be an aggravation of the breathlessness that occurs in healthy persons during activity.
  • As LV failure advances, the intensity of exercise resulting in breathlessness progressively declines; however, subjective exercise capacity and objective measures of LV performance at rest in patients with heart failure are not closely correlated. Exertional dyspnea, in fact, may be absent in sedentary patients.
• Orthopnea
• • This early symptom of CHF may be defined as dyspnea that develops in the recumbent position and is relieved with elevation of the head with pillows. As in the case of exertional dyspnea, the change in the number of pillows required is important.
  • In the recumbent position, decreased pooling of blood in the lower extremities and abdomen occurs. Blood is displaced from the extrathoracic to the thoracic compartment. The failing LV, operating on the flat portion of the Starling curve, cannot accept and pump out the extra volume of blood delivered to it without dilating. As a result, pulmonary venous and capillary pressures rise further, causing interstitial pulmonary edema, reduced pulmonary compliance, increased airway resistance, and dyspnea.
  • In contrast to paroxysmal nocturnal dyspnea, orthopnea occurs rapidly, often within a minute or two of recumbency, and develops when the patient is awake. Orthopnea may occur in any condition in which the vital capacity is low. Marked ascites, whatever its etiology, is an important cause of orthopnea. In advanced LV failure, orthopnea may be so severe that the patient cannot lie down and must sleep sitting up in a chair or slumped over a table.
  • Cough, particularly during recumbency, may be an "orthopnea equivalent." This nonproductive cough may be caused by pulmonary congestion and is relieved by treatments for heart failure.
• Paroxysmal nocturnal dyspnea
• • Attacks of paroxysmal nocturnal dyspnea usually occur at night. This symptom of CHF is defined by a sudden awakening of the patient, after a couple hours of sleep, with a feeling of severe anxiety, breathlessness, and suffocation. The patient may bolt upright in bed and gasp for breath. Bronchospasm increases ventilatory difficulty and the work of breathing and is a common complicating factor of paroxysmal nocturnal dyspnea. On chest auscultation, the bronchospasm associated with a CHF exacerbation can be difficult to distinguish from an acute asthma exacerbation, although other clues from the cardiovascular examination should lead the examiner to the correct diagnosis. Both types of bronchospasm can be present in the same individual.
  • In contrast to orthopnea, which may be relieved by immediately sitting up in bed, attacks of paroxysmal nocturnal dyspnea may require 30 minutes or longer in this position for relief. Episodes of this may be so frightening that the patient may be afraid to resume sleeping, even after the symptoms have abated.
• Dyspnea at rest - Mechanisms of dyspnea in heart failure
  • Decreased pulmonary function
  • Decreased compliance
  • Increased airway resistance
  • Increased ventilatory drive
  • Hypoxemia due to increased pulmonary capillary wedge pressure (PCWP)
  • Ventilation/perfusion (V/Q) mismatching due to increased PCWP and cardiac output
  • Increased carbon dioxide production
  • Respiratory muscle dysfunction
  • Decreased respiratory muscle strength
  • Decreased endurance
  • Ischemia
• Fatigue and weakness
• • These symptoms are often accompanied by a feeling of heaviness in the limbs.
  • Fatigue and weakness are generally related to poor perfusion of the skeletal muscles in patients with a lowered cardiac output. Although generally a constant feature of advanced CHF, episodic fatigue and weakness are common in earlier stages.
• Nocturia
• • Nocturia may occur relatively early in the course of heart failure. Recumbency reduces the deficit in cardiac output in relation to oxygen demand; renal vasoconstriction diminishes and urine formation increases. This may be troublesome for the patient with heart failure because it may prevent the patient from obtaining much-needed rest.
  • Oliguria is a late finding in CHF and is found in patients with markedly reduced cardiac output from severely reduced LV function.
• Cerebral symptoms: Confusion, memory impairment, anxiety, headaches, insomnia, bad dreams or nightmares, and rarely, psychosis with disorientation, delirium, or hallucinations may occur in elderly patients with advanced heart failure, particularly in those with cerebrovascular atherosclerosis.
• Predominant right-sided heart failure
• • Ascites, congestive hepatomegaly, and anasarca due to elevated right-sided heart pressures transmitted backward into the portal vein circulation may result in increased abdominal girth and epigastric and right upper quadrant (RUQ) abdominal pain. Other gastrointestinal symptoms, owing to congestion of the hepatic and gastrointestinal venous circulation, include anorexia, bloating, nausea, and constipation. In preterminal heart failure, inadequate bowel perfusion can cause abdominal pain, distention, and bloody stools. Distinguishing right-sided CHF from hepatic failure is often clinically difficult.
  • Dyspnea, prominent in LV failure, becomes less prominent in isolated right-sided heart failure because of the absence of pulmonary congestion. On the other hand, when cardiac output becomes markedly reduced in patients with terminal right-sided heart failure (as may occur in isolated RV infarction and in the late stages of primary pulmonary hypertension and pulmonary thromboembolic disease), severe dyspnea may occur as a consequence of the reduced cardiac output, poor perfusion of respiratory muscles, hypoxemia, and metabolic acidosis.

Physical

• General appearance
  • Patients with mild heart failure appear to be in no distress after a few minutes of rest, but they may be obviously dyspneic during and immediately after moderate activity. Patients with LV failure may be dyspneic when lying flat without elevation of the head for more than a few minutes. Those with severe heart failure appear anxious and may exhibit signs of air hunger in this position.
  • Patients with recent onset of heart failure are generally well nourished, but those with chronic severe heart failure are often malnourished and sometimes even cachectic.
  • Chronic marked elevation of systemic venous pressure may produce exophthalmos and severe tricuspid regurgitation and may lead to visible pulsation of the eyes and of the neck veins.
  • Central cyanosis, icterus, and malar flush may be evident in patients with severe heart failure.
  • In mild or moderate heart failure, stroke volume is normal at rest; in severe heart failure, it is reduced, as reflected by a diminished pulse pressure and a dusky discoloration of the skin.
  • With very severe heart failure, particularly if cardiac output has declined acutely, systolic arterial pressure may be reduced. The pulse may be weak, rapid, and thready; the proportional pulse pressure (pulse pressure/systolic pressure) may be markedly reduced. The proportional pulse pressure correlates reasonably well with cardiac output. In one study, when pulse pressure was less than 25%, it usually reflected a cardiac index of less than 2.2 L/min/m².
• Evidence of increased adrenergic activity
  • Increased adrenergic activity is manifested by tachycardia, diaphoresis, pallor, peripheral cyanosis with pallor and coldness of the extremities, and obvious distention of the peripheral veins secondary to venoconstriction.
  • Diastolic arterial pressure may be slightly elevated.
• Pulmonary rales
  • Rales heard over the lung bases are characteristic of CHF of at least moderate severity. With acute pulmonary edema, rales are frequently accompanied by wheezing and expectoration of frothy, blood-tinged sputum.
  • The absence of rales, however, certainly does not exclude elevation of pulmonary capillary pressure due to LV failure.
• Systemic venous hypertension: This is manifested by jugular venous distention. Normally, jugular venous pressure declines with respiration; however, it increases in patients with heart failure, a finding known as the Kussmaul sign (also found in constrictive pericarditis).
• Hepatojugular reflux: This is found in patients with right-sided heart failure and is helpful in differentiating hepatic enlargement due to heart failure from that caused by other conditions.
• Edema
  • Although a cardinal manifestation of CHF, edema does not correlate well with the level of systemic venous pressure. In patients with chronic LV failure and low cardiac output, extracellular fluid volume may be sufficiently expanded to cause edema in the presence of only slight elevations in systemic venous pressure.
  • Usually, a substantial gain of extracellular fluid volume (ie, a minimum of 5 L in adults) must occur before peripheral edema is manifested.
  • Edema, in the absence of dyspnea or other signs of LV or RV failure, is not solely indicative of heart failure and can be observed in many other conditions, including chronic venous insufficiency, nephrotic syndrome, or other syndromes of hypoproteinemia or osmotic imbalance.
• Hepatomegaly
  • Hepatomegaly is prominent in patients with chronic right-sided heart failure, but it may occur rapidly in acute heart failure.
  • When occurring acutely, the liver is usually tender.
  • In patients with considerable tricuspid regurgitation, a prominent systolic pulsation of the liver, attributable to an enlarged right atrial V wave, is often noted. A presystolic pulsation of the liver, attributable to an enlarged right atrial A wave, can occur in tricuspid stenosis, constrictive pericarditis, restrictive cardiomyopathy involving the RV, and pulmonary hypertension (primary or secondary).
• Hydrothorax (pleural effusion)
  • Hydrothorax is most commonly observed in patients with hypertension involving both systemic and pulmonary systems. Hydrothorax is usually bilateral, although when unilateral, it is usually confined to the right side of the chest.
  • When hydrothorax develops, dyspnea usually intensifies because of further reductions in vital capacity.
• Ascites
  • This finding occurs in patients with increased pressure in the hepatic veins and in the veins draining into the peritoneum.
  • Ascites usually reflects long-standing systemic venous hypertension.
• Protodiastolic (S₃) gallop: This is the earliest cardiac physical finding in decompensated heart failure in the absence of severe mitral or tricuspid regurgitation or left-to-right shunts.
• Cardiomegaly
  • A nonspecific finding, cardiomegaly nonetheless occurs in most patients with chronic heart failure.
  • Notable exceptions include heart failure from acute myocardial infarction, constrictive pericarditis, restrictive cardiomyopathy, valve or chordae tendineae rupture, or heart failure due to tachyarrhythmias or bradyarrhythmias.
• Pulsus alternans
  • Pulsus alternans occurs most commonly in heart failure due to increased resistance to LV ejection, as occurs in hypertension, aortic stenosis, coronary atherosclerosis, and dilated cardiomyopathy.
  • It is usually associated with an S₃ gallop, signifies advanced myocardial disease, and often disappears with treatment of heart failure.
• Accentuation of P₂ heart sound, S₃ gallop, and systolic murmurs
  • This accentuation is a cardinal sign of increased pulmonary artery pressure. It disappears or improves after treatment of heart failure.
  • Mitral and tricuspid regurgitation murmurs are often present in patients with decompensated heart failure because of ventricular dilatation. These murmurs often disappear or diminish when compensation is restored. Note that correlation between the intensity of the murmur of mitral regurgitation and its significance in patients with CHF is poor. Severe mitral regurgitation may be accompanied by an unimpressively soft murmur.
  • The presence of an S₃ gallop in adults is important, pathologic, and often the most apparent finding on cardiac auscultation in patients with significant CHF.
• Cardiac cachexia
  • Cardiac cachexia is found in long-standing heart failure, particularly of the RV, because of anorexia from hepatic and intestinal congestion and sometimes because of digitalis toxicity. Occasionally, impaired intestinal absorption of fat and (rarely) protein-losing enteropathy occur.
  • Patients with heart failure may also exhibit increased total metabolism secondary to augmentation of myocardial oxygen consumption, excessive work of breathing, low-grade fever, and elevated levels of circulating TNF.
• Fever: Fever may be present in severe decompensated heart failure because of cutaneous vasoconstriction and impairment of heat loss.

Causes

From a clinical standpoint, it is useful to classify the causes of heart failure into 3 broad categories: (1) underlying causes, comprising structural abnormalities (congenital or acquired) that affect the peripheral and coronary arterial circulation, pericardium, myocardium, or cardiac valves, thus leading to the increased hemodynamic burden or myocardial or coronary insufficiency responsible for heart failure; (2) fundamental causes, comprising the biochemical and physiological mechanisms, through which either an increased hemodynamic burden or a reduction in oxygen delivery to the myocardium results in impairment of myocardial contraction; and (3) precipitating causes, including the specific causes or incidents that precipitate heart failure in most episodes of heart failure.

Note that most patients who present with significant heart failure do so because of an inability to provide adequate cardiac output in that setting. This is often a combination of the causes listed above in the setting of an abnormal myocardium. The list of causes responsible for presentation of a patient with a CHF exacerbation is very long, and it is important to search for the proximate cause in order to optimize therapeutic interventions.

Overt heart failure may be precipitated by progression of the underlying heart disease. A previously stable compensated patient may develop heart failure that is clinically apparent for the first time when the intrinsic process has advanced to a critical point, such as with further narrowing of a stenotic aortic valve or mitral valve. Alternatively, decompensation may occur as a result of failure or exhaustion of the compensatory mechanisms but without any change in the load on the heart in patients with persistent severe pressure or volume overload.

• Precipitating causes of heart failure
• • Inappropriate reduction of therapy: The most common cause of decompensation in a previously compensated patient with heart failure is inappropriate reduction in the intensity of treatment, whether dietary sodium restriction, physical activity reduction, drug regimen reduction, or, most commonly, a combination of these measures.
  • Arrhythmias
    • Tachyarrhythmias, most commonly atrial fibrillation
    • Marked bradycardia
    • Atrioventricular dissociation
    • Abnormal intraventricular conduction
  • Systemic infection or development of unrelated illness
    • Systemic infection precipitates heart failure by increasing total metabolism as a consequence of fever, discomfort, and cough, which increases the hemodynamic burden on the heart.
    • Septic shock, in particular, can precipitate heart failure by the release of endotoxin-induced factors that can depress myocardial contractility.
  • Pulmonary embolism: Patients with CHF, particularly when confined to bed, are at high risk of developing pulmonary emboli, which can increase the hemodynamic burden on the RV by further elevating RV systolic pressure, possibly causing fever, tachypnea, and tachycardia.
  • Physical, environmental, and emotional excesses: Intense, prolonged physical exertion or severe fatigue, such as may result from prolonged travel or emotional crises, or severe climate changes, either to a hot, humid environment or to a bitterly cold environment, are relatively common precipitants of cardiac decompensation.
  • Cardiac infection and inflammation
    • Myocarditis or infective endocarditis may directly impair myocardial function and exacerbate existing heart disease. The anemia, fever, and tachycardia that frequently accompany these processes are also deleterious.
    • In the case of infective endocarditis, the additional valvular damage that ensues may precipitate cardiac decompensation.
  • Excessive intake of water and/or sodium
  • Administration of cardiac depressants or drugs that cause salt retention
  • High-output states: Profound anemia, thyrotoxicosis, myxedema, Paget disease of bone, Albright syndrome, multiple myeloma, glomerulonephritis, cor pulmonale, polycythemia vera, obesity, carcinoid syndrome, pregnancy, or nutritional deficiencies (eg, thiamine deficiency, beriberi) can precipitate the clinical presentation of CHF because of increased myocardial oxygen consumption and demand beyond a critical level (ie, beyond the ability of the underlying myocardial oxygen supply to meet these demands). In particular, consider whether the patient has underlying coronary artery disease or valvular heart disease.
  • Development of a second form of heart disease
    • Patients with one form of underlying heart disease that may be well compensated can develop heart failure when a second form of heart disease ensues.
    • For example, a patient with chronic hypertension and asymptomatic LV hypertrophy may be asymptomatic until a myocardial infarction develops and precipitates heart failure.
• Underlying causes
• • Dominant systolic heart failure
    • Ischemic myocardial disease, coronary artery disease
    • Alcoholic cardiomyopathy
    • Diabetic cardiomyopathy
    • Cocaine cardiomyopathy
    • Drug-induced cardiomyopathy (eg, doxorubicin)
    • Idiopathic cardiomyopathy
    • Peripartum cardiomyopathy
    • Myocarditis
    • Preterminal valvular heart disease
    • Congenital heart disease with severe pulmonary hypertension
    • Terminal ventricular septal defect or atrial septal defect
  • Dominant diastolic heart failure
    • Hypertension
    • Severe aortic stenosis
    • Hypertrophic cardiomyopathy
    • Restrictive cardiomyopathy
    • Ischemic myocardial disease, coronary artery disease
  • Acute heart failure
    • Acute mitral or aortic regurgitation
    • Rupture of valve leaflets or supporting structures
    • Infective endocarditis with acute valve incompetence
    • Myocardial infarction
  • High-output heart failure
    • Anemia
    • Systemic arteriovenous fistulas
    • Hyperthyroidism
    • Beriberi heart disease
    • Paget disease of bone
    • Albright syndrome (fibrous dysplasia)
    • Multiple myeloma
    • Pregnancy
    • Glomerulonephritis
    • Cor pulmonale
    • Polycythemia vera
    • Carcinoid syndrome
    • Obesity

DIFFERENTIALS

Asthma
Cardiogenic Shock
Chronic Bronchitis
Chronic Obstructive Pulmonary Disease
Emphysema
Goodpasture Syndrome
Myocardial Infarction
Myocardial Ischemia
Pneumocystis Carinii Pneumonia
Pneumonia, Bacterial
Pneumonia, Community-Acquired
Pneumonia, Viral
Pneumothorax
Pulmonary Edema, Cardiogenic
Pulmonary Edema, High-Altitude
Pulmonary Edema, Neurogenic
Pulmonary Embolism
Pulmonary Fibrosis, Idiopathic
Pulmonary Fibrosis, Interstitial (Nonidiopathic)
Respiratory Failure

 

Other Problems to be Considered

CHF should be differentiated from pulmonary edema associated with injury to the alveolar-capillary membrane caused by diverse etiologies (ie, noncardiogenic pulmonary edema, adult respiratory distress syndrome [ARDS]). Increased capillary permeability is observed in trauma, hemorrhagic shock, sepsis, respiratory infections, administration of various drugs, and ingestion of toxins such as heroin, cocaine, and toxic gases.

Several features may differentiate cardiogenic heart failure from noncardiogenic pulmonary edema. In CHF, a history of an acute cardiac event or that of progressive symptoms of heart failure is usually present. The physical examination reveals a low-flow state, S₃ gallop, elevated jugular venous distention, and crackles upon auscultation.

Patients with noncardiogenic pulmonary edema have a warm periphery, a bounding pulse, and an absence of S₃ gallop and jugular venous distention. Differentiation is often made based on PCWP measurements from invasive hemodynamic monitoring. PCWP is generally more than 18 mm Hg in CHF and is less than 18 mm Hg in noncardiogenic pulmonary edema, but superimposition of chronic pulmonary vascular disease can make this distinction more difficult to discern. With the advent of BNP level testing, reliably differentiating cardiac causes of pulmonary congestion from noncardiac causes is now possible.

 

WORKUP

Lab Studies

• CBC count: This study aids in the assessment of severe anemia, which may cause or aggravate heart failure. Leukocytosis may signal underlying infection. Otherwise, CBC counts are usually of little diagnostic help.
• Electrolytes
  • Serum electrolyte values are generally within reference ranges in patients with mild-to-moderate heart failure before treatment. However, in severe heart failure, prolonged, rigid sodium restriction, coupled with intensive diuretic therapy and the inability to excrete water, may lead to dilutional hyponatremia, which occurs because of a substantial expansion of extracellular fluid volume and a normal or increased level of total body sodium.
  • Potassium levels are usually within reference ranges, although the prolonged administration of diuretics may result in hypokalemia. Hyperkalemia may occur in patients with severe heart failure who show marked reductions in GFR and inadequate delivery of sodium to the distal tubular sodium-potassium exchange sites of the kidney, particularly if they are receiving potassium-sparing diuretics and/or ACE inhibitors.
• Renal function tests
  • BUN and creatinine levels can be within reference ranges in patients with mild-to-moderate heart failure and normal renal function, although elevated BUN and BUN/creatinine ratios may also be present.
  • Patients with severe heart failure, particularly those on large doses of diuretics for long periods, may have elevated BUN and creatinine levels indicative of renal insufficiency because of chronic reductions of renal blood flow from reduced cardiac output. Diuretics may aggravate renal insufficiency when these patients are overmedicated with diuretics and become volume depleted.
• Liver function tests
  • Congestive hepatomegaly and cardiac cirrhosis are often associated with impaired hepatic function, which is characterized by abnormal values of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactic dehydrogenase (LDH), and other liver enzymes.
  • Hyperbilirubinemia, secondary to an increase in both the directly and indirectly reacting bilirubin, is common. In severe cases of acute RV or LV failure, frank jaundice may occur.
  • Acute hepatic venous congestion can result in severe jaundice, with a bilirubin level as high as 15-20 mg/dL, elevation of AST to more than 10 times the upper reference range limit, elevation of the serum alkaline phosphatase level, and prolongation of the prothrombin time. Both the clinical and the laboratory pictures may resemble viral hepatitis, but the impairment of hepatic function is rapidly resolved by successful treatment of heart failure. In patients with long-standing heart failure, albumin synthesis may be impaired, leading to hypoalbuminemia and intensifying the accumulation of fluid.
  • Fulminant hepatic failure is an uncommon, late, and sometimes terminal complication of cardiac cirrhosis.
• B-type natriuretic peptide
  • BNP is a 32-amino acid polypeptide containing a 17-amino acid ring structure common to all natriuretic peptides. Unlike ANP, whose major storage sites are in both the atria and ventricles, the major source of plasma BNP is the cardiac ventricles, suggesting that BNP may be a more sensitive and specific indicator of ventricular disorders than other natriuretic peptides. The release of BNP appears to be in direct proportion to ventricular volume expansion and pressure overload. BNP is an independent predictor of high LV end-diastolic pressure and is more useful than ANP or NE levels for assessing mortality risk in patients with CHF.
  • BNP levels rise with age. Mean BNP levels are 26.2 +/- 1.8 pg/mL in the group aged 55-64 years, 31.0 +/- 2.4 pg/mL for the group aged 65-74 years, and 63.7 +/- 6 pg/mL for the group aged 75 years and older. Additionally, women without CHF tend to have somewhat higher BNP levels than their male cohorts of the same age, with women 75 years and older having a mean BNP level of 76.5 +/- 3.5 pg/mL. Although the reason is unknown, aging women possibly have stiffer ventricles than age-matched men.
  • BNP levels correlate closely with the NYHA Classification of Heart Failure as well as the Goldman Activity Classification of Heart Failure.
  • BNP levels of more than 100 pg/mL have better than a 95% specificity and greater than a 98% sensitivity when comparing patients without CHF to all patients with CHF. Even BNP levels of more than 80 pg/mL have greater than a 93% specificity and 98% sensitivity in the diagnosis of heart failure. Furthermore, BNP levels, in several pilot studies, had a strong correlation with the severity of illness and were very reliable in differentiating CHF from pulmonary disease.
  • BNP levels also correlate highly with the change in PCWP pressure. It has been proposed that BNP levels may be a useful surrogate indicator of PCWP, although this is not common in clinical practice. BNP may help in tailoring treatment of the decompensated patient.
  • In a pilot study, BNP levels correlated highly with clinical outcomes. Patients with decreased BNP levels during their hospital stay, along with decreases in NYHA classification, had good outcomes, whereas patients whose hospital stay ended in death or readmission within 30 days of discharge had only minimal decreases of BNP levels or rising levels of BNP despite improvement or no change in their NYHA classification. In addition, the last measured BNP level was the single most reliable variable in predicting short-term outcomes in patients with CHF.

Imaging Studies

• Chest radiography
• • Chest radiographs are very helpful in distinguishing cardiogenic pulmonary edema (CPE) from other pulmonary causes of severe dyspnea.
  • Classic radiographic findings demonstrate cardiomegaly (in patients with underlying CHF) and alveolar edema with pleural effusions and bilateral infiltrates in a butterfly pattern. The other signs are loss of sharp definition of pulmonary vasculature, haziness of hilar shadows, and thickening of interlobular septa (Kerley B lines).
  • Chest radiographs in patients with abrupt onset are usually helpful but can be limited because a delay of as long as 12 hours is possible from the onset of dyspnea due to acute heart failure to the development of classic abnormal findings on x-ray films.
• Echocardiography
• • This is the easiest and least-expensive method of determining LV function, both systolic and diastolic. Echocardiography is also the easiest and least-expensive method of determining the presence of valvular heart disease, LV wall thickness, chamber sizes, presence of pericardial disease, and regional wall motion abnormalities that may suggest ischemic coronary artery disease as the cause. Echocardiography is very reliable in diagnosing the cause or causes of heart failure.
  • Transesophageal echocardiography is particularly useful in patients who are on mechanical ventilation or morbidly obese and in patients whose transthoracic echocardiogram was suboptimal in its imaging. It is an easy and safe alternative to conventional transthoracic echocardiography and provides superior imaging quality compared to conventional transthoracic echocardiography.
• Radionuclide multiple gated acquisition scan
• • Radionuclide multiple gated acquisition (MUGA) scan is a very reliable imaging technique for determining global heart function. LV ejection fraction, as determined by MUGA scanning, is often used for serial assessment of LV function because of its reliability.
  • However, this study is limited in its assessment of valvular heart disease and pericardial disease.

Other Tests

• Arterial blood gases
• • ABGs usually reveal mild hypoxemia in patients who have mild-to-moderate heart failure. ABGs are more accurate than pulse oximetry for measuring oxygen saturation. Patients with severe heart failure may have signs and symptoms ranging from severe hypoxemia, or even hypoxia, along with hypercapnia, to decreased vital capacity and poor ventilation.
  • ABGs help to assess the presence of hypercapnia, a potential early marker for impending respiratory failure. Hypoxemia and hypocapnia occur in stages 1 and 2 of pulmonary edema because of V/Q mismatch. In stage 3 of pulmonary edema, right-to-left intrapulmonary shunt develops secondary to alveolar flooding and further contributes to hypoxemia. In more severe cases, hypercapnia and respiratory acidosis are usually observed. The decision regarding intubation and use of mechanical ventilation is frequently based on the presence of hypercapnic respiratory failure with acidosis discovered on ABGs in patients with fulminant pulmonary edema.
• Pulse oximetry
• • Pulse oximetry is highly accurate at assessing the presence of hypoxemia and, therefore, the severity of heart failure.
  • Patients with mild-to-moderate heart failure show modest reductions in oxygen saturation, whereas patients with severe heart failure may have severe oxygen desaturation, even at rest.
  • Patients with mild-to-moderate heart failure may have normal oxygen saturations at rest, but they may exhibit marked reductions in oxygen saturations during physical exertion or recumbency, necessitating the use of continuous oxygen until compensation either returns oxygen saturation to normal during exertion and recumbency or on a permanent basis if oxygen desaturation during exertion and/or recumbency exist during compensated severe heart failure.
  • Pulse oximetry is useful for monitoring the patient's response to supplemental oxygen and other therapies.
• Electrocardiography
• • The presence of left atrial enlargement and LV hypertrophy is sensitive (although nonspecific) for chronic LV dysfunction.
  • ECG may suggest an acute tachyarrhythmia or bradyarrhythmia as the cause of heart failure.
  • ECG may aid in the diagnosis of acute myocardial ischemia or infarction as the cause of heart failure or may suggest the likelihood of prior myocardial infarction or presence of coronary artery disease as the cause of heart failure.
  • ECG is of limited help when an acute valvular abnormality or LV systolic dysfunction is considered to be the cause of heart failure; however, the presence of left bundle branch block (LBBB) on an ECG is a strong marker for diminished LV systolic function.

Procedures

• Right-sided heart catheterization
• • PCWP can be measured by using a pulmonary arterial catheter (Swan-Ganz catheter), and this helps differentiate cardiogenic causes of decompensated heart failure from noncardiogenic causes such as ARDS, which occurs secondary to injury to the alveolar-capillary membrane rather than to alteration in Starling forces. A PCWP exceeding 18 mm Hg in a patient not known to have chronically elevated left atrial pressure is indicative of cardiogenic decompensated heart failure. In patients with chronic pulmonary capillary hypertension, capillary wedge pressures exceeding 30 mm Hg are generally required to overcome the pumping capacity of the lymphatics and produce pulmonary edema.
  • Large V waves may sometimes be observed in the PCWP tracing with acute mitral regurgitation because large volumes of blood regurgitate into a poorly compliant left atrium. This raises pulmonary venous pressure and causes acute pulmonary edema. The pulmonary artery waveform appears falsely elevated because of the large V wave reflected from the left atrium through the compliant pulmonary vasculature. The Y descent of the waveform is quite rapid as the overdistended left atrium quickly empties. Patients with long-standing mitral regurgitation and left atrial enlargement may demonstrate much less impressive V waves even in the setting of very significant mitral regurgitation.
  • Cardiogenic shock is the result of a severe depression in myocardial function. Although many definitions for cardiogenic shock have been proposed, the following provides a useful guideline: Cardiogenic shock is present when systolic blood pressure is less than 80 mm Hg, the cardiac index is less than 1.8 L/min/m², and the PCWP is greater than 18 mm Hg. This form of shock can occur from a direct insult to the myocardium (eg, large acute myocardial infarction, severe cardiomyopathy) or from a mechanical problem that overwhelms the functional capacity of the myocardium (eg, acute severe mitral regurgitation, acute ventricular septal defect). The prognosis of patients with cardiogenic shock is poor, with in-hospital mortality rates of 50-90%.
• Left-sided heart catheterization and coronary angiography
• • Left-sided heart catheterization and coronary angiography should be undertaken when the etiology of heart failure cannot be determined by clinical or noninvasive imaging methods or when the etiology is likely to be due to acute myocardial ischemia or myocardial infarction. Coronary angiography is particularly helpful in patients with LV systolic dysfunction and known or suspected coronary artery disease in whom myocardial ischemia is thought to play a dominant role in the reduction of LV systolic function and the worsening of heart failure. As a general rule, most patients with clinically significant CHF should undergo cardiac catheterization to exclude the reversible causes listed above.
  • Specific rationales for right- and left-sided heart catheterization include the need to determine the etiologic significance and severity of mitral and/or aortic valvular disease in patients with heart failure in whom the cause-effect relationship of valvular heart disease with regard to heart failure is unclear. Furthermore, right- and left-sided heart catheterization should be performed in patients in whom constrictive pericarditis is considered a likely cause of heart failure.

Staging

• A classification of patients with heart disease based on the relation between symptoms and the amount of effort required to provoke them has been developed by the NYHA.
  • Class I: No limitations. Ordinary physical activity does not cause undue fatigue, dyspnea, or palpitations.
  • Class II: Slight limitation of physical activity. Such patients are comfortable at rest. Ordinary physical activity results in fatigue, palpitations, dyspnea, or angina.
  • Class III: Marked limitation of physical activity. Although patients are comfortable at rest, less-than-ordinary activity leads to fatigue, dyspnea, palpitations, or angina.
  • Class IV: Symptomatic at rest. Symptoms of CHF are present at rest; discomfort increases with any physical activity.
• The Goldman Activity Classification of Heart Failure is based on estimated metabolic cost of various activities, and classes correlate to NYHA classes.
  • Class I: Patients can perform to completion any activity up to 7 metabolic equivalents (METS).
  • Class II: Patients can perform to completion any activity up to 5 METS of activity but cannot perform to completion any activities equal to or more than 7 METS.
  • Class III: Patients can perform to completion any activity up to 2 METS of activity but cannot perform to completion any activities equal to or more than 5 METS.
  • Class IV: Patients cannot perform to completion activities equal to or more than 2 METS.

 

TREATMENT

Medical Care

Medical therapy of heart failure focuses on 3 main goals: (1) preload reduction, (2) reduction of systemic vascular resistance (afterload reduction), and (3) inhibition of both the RAAS systems and vasoconstrictor neurohumoral factors produced by the sympathetic nervous system in patients with heart failure. The first 2 goals provide symptomatic relief. While reducing symptoms, inhibition of the RAAS and neurohumoral factors also results in significant reductions in morbidity and mortality rates.

Preload reduction results in decreased pulmonary capillary hydrostatic pressure and reduction of fluid transudation into the pulmonary interstitium and alveoli. Afterload reduction results in increased cardiac output and improved renal perfusion, which allows for diuresis in the patient with fluid overload. Inhibition of the RAAS and sympathetic nervous system results in favored vasodilation and reduction of neurohumoral vasoconstrictors, thereby increasing cardiac output and reducing blood volume and myocardial oxygen demand.

Patients with severe LV dysfunction or acute valvular disorders may present with hypotension. These patients may not tolerate medications to reduce their preload and afterload and may require inotropic support to maintain adequate blood pressure.

Patients who remain hypoxic despite supplemental oxygen or who demonstrate severe respiratory distress require mechanical ventilation, in addition to maximal medical therapy.

• Preload reduction
  • Nitroglycerin
  • Nitroglycerine (NTG) is the most effective, predictable, and rapid-acting medication available for preload reduction.
  • Multiple studies comparing NTG to furosemide or morphine sulfate have demonstrated greater efficacy and safety and a faster onset of action for NTG.
  • Use of sublingual NTG is associated with preload reduction within 5 minutes and some afterload reduction.
  • Topical NTG may be as effective as sublingual NTG in most patients with heart failure, but it should be avoided in patients with severe LV failure because of poor skin perfusion (manifesting as skin pallor or mottling) and resultant poor absorption.
  • Intravenous NTG at higher dosages provides rapid and titratable preload and afterload reduction and has been demonstrated to be an excellent single-agent therapy for patients with severe decompensated CHF.
  • Loop diuretics
  • Loop diuretics are the cornerstone of heart failure treatment and have been considered as such for many decades. Furosemide is most commonly used. Bumetanide has a higher bioavailability and may be more effective in patients with severe CHF.
  • Loop diuretics are presumed to decrease preload through 2 mechanisms: diuresis and direct pulmonary artery vasodilation and venodilation.
  • In most patients, diuresis does not occur for at least 20-90 minutes; thus, the effect is delayed.
  • In some patients with heart failure, particularly those with diastolic heart failure who are minimally fluid overloaded, continued diuretic use after resolution of acute symptoms may be associated with adverse outcomes, including electrolyte derangements and hypotension.
  • Use of medications that decrease preload (eg, NTG) and afterload (eg, ACE inhibitors), either concomitantly or before the administration of loop diuretics, can prevent potential adverse hemodynamic changes.
  • Potassium-sparing diuretics
  • Numerous studies have shown spironolactone to be as beneficial in the management of CHF as loop diuretics.
  • Some of the beneficial effects of spironolactone may be due to its neurohormonal actions.
  • Morphine sulfate
  • Morphine sulfate use in acute CHF for preload reduction has been commonplace for many years.
  • Use should be weighed against potential adverse effects (eg, nausea/vomiting, local or systemic allergic reactions, respiratory depression) that may outweigh any potential benefit, especially given the availability of much more effective medications for preload reduction (eg, NTG).
  • Any beneficial hemodynamic effect probably is due to anxiolysis, with a resulting decrease in catecholamine production and systemic vascular resistance.
• Vasodilators (combined afterload and preload reducers)
  • ACE inhibitors
  • Although initial studies focused on the efficacy of ACE inhibitors in the treatment of chronic CHF, recent studies have demonstrated excellent results for treatment of acute decompensated CHF.
  • Studies demonstrate that the use of ACE inhibitors in acute heart failure is associated with reduced admission rates to ICUs and decreased endotracheal intubation rates.
  • Hemodynamic effects of ACE inhibitors include reduced afterload, improved stroke volume and cardiac output, and reduced preload.
  • ACE inhibitors must be initiated with extreme care in individuals presenting with borderline hemodynamic parameters.
  • When administered by intravenous (enalapril 1.25 mg) or sublingual routes, hemodynamic and subjective improvements are noted within 10 minutes; improvements occur more slowly with the oral route.
  • ACE inhibitors prolong survival in heart failure. Furthermore, compared to the combination of hydralazine and long-acting nitrates, ACE inhibitors showed a trend to a greater prolongation of survival, had improved hemodynamics, and were better tolerated.
  • Ang II receptor inhibitors
  • Ang receptor inhibitors, such as losartan and candesartan, are highly recommended alternatives to ACE inhibitors in patients who cannot tolerate ACE inhibitors because of adverse effects, most notably, coughing.
  • Furthermore, these agents have gained wider use based on their low adverse effect profile and early study findings, which indicated that combined ACE inhibition and Ang II receptor inhibition is beneficial.
  • Hydralazine
  • Hydralazine was the first oral balanced (afterload and preload reduction) vasodilator and was popular before the availability of ACE inhibitors. It is a direct vasodilator, unlike ACE inhibitors or Ang receptor inhibitors, which are vasodilators through inhibition of the RAAS system.
  • When combined with long-acting nitrates, hydralazine was shown, in the Veterans Administration Heart Failure Trial (VHEFT) studies, to prolong survival in patients with CHF.
  • Hydralazine has one main advantage over ACE inhibitors in that it is safe in pregnancy. It also is not known to worsen renal function in patients with heart failure who have reduced renal function and is not associated with the risk of hyperkalemia. Additionally, hydralazine use is recommended in patients who cannot tolerate ACE inhibitors.
  • Hydralazine, as a single agent, has less reduction in myocardial oxygen demand than ACE inhibitors because of a slight increase in heart rate that usually results from its use.
  • Nitroprusside
  • Nitroprusside results in simultaneous preload and afterload reduction through direct smooth muscle relaxation, although it has a greater effect on afterload.
  • Afterload reduction is associated with increased cardiac output.
  • Potency and rapidity of onset and offset of effect make this an ideal medication for patients who are critically ill.
  • It may induce precipitous falls in blood pressure; intraarterial blood pressure monitoring often is recommended.
  • Use nitroprusside cautiously in the setting of acute myocardial infarction because of its potential to induce hypotension.
  • If nitroprusside is used, convert patients to oral or alternative intravenous vasodilator therapy as soon as possible because prolonged use is associated with thiocyanate toxicity.
  • Use in pregnancy is associated with fetal thiocyanate toxicity.
• Inotropic support
  • Digoxin (cardiac glycoside)
  • Digoxin has been a cornerstone for the treatment of heart failure for decades and is the only oral inotropic support agent currently used in clinical practice.
  • Digoxin acts by inhibiting the Na⁺/K⁺–ATPase transport pump and inhibits sodium and potassium transport across cell membranes. This increases the velocity and shortening of cardiac muscle, resulting in a shift upward and to the left of the ventricular function (Frank-Starling) curve relating stroke volume to filling volume or pressure. This occurs in healthy as well as failing myocardium and in atrial as well as ventricular muscle. The positive inotropic effect is due to an increase in the availability of cytosolic calcium during systole, thus increasing the velocity and extent of myocardial sarcomere shortening.
  • No evidence indicates that digoxin affects peripheral vascular resistance or systemic blood pressure.
  • All evidence suggests that digoxin provides, even in the short term, a moderate and metabolically efficient positive inotropic effect, an important consideration in ischemic cardiomyopathies.
  • Although the incidence and severity of digitalis intoxication is decreasing, vigilance for this important complication of therapy is essential. Drugs that interact with digoxin are numerous and include amiodarone, propafenone, quinidine, verapamil, nifedipine, diltiazem, levothyroxine, cyclosporine, flecainide, disopyramide, omeprazole, tetracycline, and erythromycin. These agents affect clearance or absorption of digoxin, thus necessitating dose alteration of digoxin in patients taking these medications. Furthermore, patients with renal insufficiency may need to have their digoxin dose adjusted downward to avoid digitalis intoxication.
  • Numerous studies confirm that digoxin does not prolong survival in patients with systolic heart failure, but it is associated with reduced hospital admissions, improved functional class, reduced symptoms of heart failure, and improved quality of life.
  • Digoxin is also an effective agent against atrial tachyarrhythmias at rest in patients with LV dysfunction, but it has limited efficacy in controlling the ventricular rate of atrial arrhythmias during exertion.
  • Dobutamine (sympathomimetic agent)
  • Dobutamine mainly serves as a beta1-receptor agonist, although it has some beta2-receptor and minimal alpha-receptor activity.
  • Intravenous dobutamine induces significant positive inotropic effects with mild chronotropic effects. It also induces mild peripheral vasodilation (decrease in afterload).
  • The combination effect of increased inotropy with decreased afterload results in a significant increase in cardiac output.
  • Combination use with intravenous NTG may be ideal for patients with myocardial infarction and decompensated heart failure and mild hypotension in order to provide simultaneous preload reduction with increased cardiac output. In the setting of acute myocardial infarction, dobutamine use could increase infarct size because of the increase in myocardial oxygen consumption that may ensue.
  • In general, avoid dobutamine in patients with moderate or severe hypotension (eg, systolic blood pressure <80 mm Hg) because of the peripheral vasodilation.
  • Dopamine (sympathomimetic agent)
  • Vascular and myocardial receptor effects are dose dependent.
  • Low dosages (0.5-3 mcg/kg/min) cause stimulation of dopaminergic receptors within the renal and splanchnic vascular beds, causing vasodilation and increased diuresis.
  • Moderate dosages (3-10 mcg/kg/min) cause stimulation of beta-receptors in the myocardium, resulting in increased cardiac contractility and heart rate.
  • High dosages (10-20 mcg/kg/min) cause stimulation of alpha-receptors, resulting in peripheral vasoconstriction (increased afterload), increased blood pressure, and no further improvement in cardiac output.
  • As with other inotropic agents, moderate and high dosages are arrhythmogenic and also result in increased myocardial oxygen demand (potential for myocardial ischemia); therefore, use dopamine only in patients with heart failure who cannot tolerate the use of dobutamine because of severe hypotension (eg, systolic blood pressure <60-80 mm Hg).
  • NE (sympathomimetic agent)
  • NE primarily stimulates alpha-receptors, resulting in significant increases in afterload (and potential myocardial ischemia) and reduced cardiac output.
  • Use of NE is generally reserved for patients with profound hypotension (eg, systolic blood pressure <60 mm Hg). Once blood pressure is restored, add other medications to maintain cardiac output.
  • Phosphodiesterase inhibitors (milrinone, amrinone)
  • Phosphodiesterase inhibitors (PDIs) increase intracellular cAMP, which results in a positive inotropic effect on the myocardium and peripheral vasodilation (decreased afterload) and a reduction in pulmonary vascular resistance (decreased preload).
  • PDIs, unlike catecholamine inotropes, are not dependent on adrenoreceptor activity; therefore, patients are less likely to develop tolerance to these medications. Tolerance to catecholamine inotropes can develop rapidly through down-regulation of the adrenoreceptors.
  • PDIs are less likely than catecholamine inotropes to cause adverse effects that are typically associated with adrenoreceptor activity (eg, increased myocardial oxygen demand, myocardial ischemia).
  • Several studies directly comparing the use of PDIs (milrinone, amrinone) to dobutamine in patients with heart failure have demonstrated that milrinone produced equal or greater improvements in stroke volume, cardiac output, PCWPs (preload), and systemic vascular resistance (afterload). They are also associated with less tachycardia and myocardial oxygen consumption. However, PDIs have been associated with a significantly greater incidence of adverse events (eg, tachyarrhythmias) than has dobutamine.
  • At present, oral PDIs have no role. Their use was associated with a 53% increase in mortality rates in patients with NYHA Class IV heart failure in the Prospective Randomized Milrinone Survival Evaluation (PROMISE) trial, prompting an early termination of that study.
  • Unfavorable results were also evident in a smaller trial that compared oral milrinone to digoxin or placebo. Furthermore, sustained hemodynamic improvement with oral milrinone was lacking, and the incidence of adverse events, particularly cardiac arrhythmias, was greater.
• Beta-adrenergic blocking agents (metoprolol, carvedilol)
  • A large and increasing body of evidence indicates that these agents improve symptoms, exercise tolerance, cardiac hemodynamics, and LV ejection fraction and that they decrease mortality rates in patients with heart failure, particularly those with both ischemic and idiopathic cardiomyopathy.
  • A growing body of evidence suggests that long-term beta-adrenergic antagonist administration improves cardiac function, reduces myocardial ischemia, improves ventricular-arterial coupling, and decreases myocardial oxygen consumption. These agents may also reduce the incidence of sudden death due to primary ventricular arrhythmias in patients with heart failure, although this latter benefit has yet to be definitively proven.
  • Detectable improvements in ventricular function are usually not apparent for a minimum of 1-3 months, and longer-term structural changes, such as a decline in ventricular volume or mass, may take 12-18 months.
  • Beta-adrenergic antagonists with vasodilator activity, such as carvedilol and labetalol, have the added benefit of further afterload reduction because of arterial vasodilation from alpha1-receptor blockade.
• Treatment of heart failure with predominant diastolic dysfunction: The therapeutic approach to diastolic dysfunction has 2 major components. The first involves attempts to reverse the abnormal cardiac diastolic properties. The second is directed toward reducing LV filling pressure and thereby venous congestion.
  • Treatment of diastolic dysfunction
  • Pericardiectomy for constrictive pericarditis
  • Relief of ventricular systolic overload
  • ACE inhibitors and Ang receptor inhibitors slow, arrest, or even reverse myocardial fibrosis in the presence of systolic overload, thus improving diastolic dysfunction.
  • Anti-ischemic agents, such as beta-adrenergic blocking agents, calcium channel blocking agents, and nitroglycerin, are effective in immediately improving diastolic dysfunction in patients with coronary artery disease by eliminating or reducing myocardial ischemia, thus improving ventricular relaxation. Thrombolysis, mechanical revascularization (percutaneous transluminal coronary angioplasty [PTCA]), and coronary artery bypass graft surgery (CABGS), in combination with anti-ischemic agents or alone, all improve diastolic function in patients with acute and chronic myocardial ischemia by improving ventricular relaxation.
  • Calcium channel antagonists, especially verapamil, accelerate ventricular relaxation, particularly in patients with hypertensive heart disease and hypertrophic cardiomyopathy, and are useful in the treatment of diastolic dysfunction.

• Regression of ventricular hypertrophy

• Aggressive control of hypertension with beta-adrenergic blocking agents, calcium channel blocking agents, diuretics, ACE inhibitors, Ang receptor inhibitors, and central-acting antihypertensive agents (eg, methyldopa) reduces ventricular hypertrophy, thereby improving diastolic function.
• Aortic valve replacement for aortic stenosis also reduces ventricular hypertrophy and improves diastolic function.
• Relief of valvular, supravalvular, and subvalvular obstruction to ventricular outflow by operation or balloon valvuloplasty improves diastolic function by relieving ventricular pressure overload, thus regressing ventricular hypertrophy.

• Reduction of ventricular filling pressure and secondary venous congestion: These approaches are usually highly effective in patients presenting with a CHF exacerbation primarily caused by a diastolic dysfunction. Indeed, a hallmark of diastolic dysfunction is the rapid improvement in response to the therapies described below.

• Restriction of dietary sodium
• Administration of diuretics and venodilators
• Administration of NTG or long-acting nitrates
• Maintenance of normal heart rate and rhythm: Digoxin has no established place in the management of patients with predominant diastolic dysfunction and well-preserved ventricular ejection fraction, and it could potentially have an adverse effect in this group of patients.

• Newer therapies for heart failure

• Nesiritide, a recombinant BNP, is from an exciting new class of peptides that has several unique properties.
  • Nesiritide is a balanced vasodilator, slightly more venous than arterial, rapidly improves symptoms of congestion, does not increase heart rate, decreases myocardial oxygen demand, and is not proarrhythmic.
  • Nesiritide decreases aldosterone and ET-1 release through neurohumoral suppression, does not exhibit tachyphylaxis, and induces a mild diuresis and natriuresis. It significantly reduces ventricular filling pressures to a greater extent than standard care with ACE inhibitors and diuretics, even more than the combination of ACE inhibitors, diuretics, and nitroglycerin.
  • Nesiritide should be avoided in patients with systolic blood pressure of less than 80-85 mm Hg. The primary adverse event (occurring in 4% of the patients in the Veterans Administration Medical Center [VAMC] study on nesiritide) was hypotension.
  • Nesiritide has no drug interactions with any of the other treatments used in CHF, thus making it useful as an effective adjunct in patients with severe, acute decompensated CHF without cardiogenic shock.
  • Study results indicate that treatment with nesiritide could lead to a reduced length of stay in the critical care unit, decreased recurrence of decompensation, and less likelihood of rehospitalization.
• Eplerenone, a selective aldosterone-blocking agent, has been shown to reduce rates of all-cause mortality, cardiovascular mortality, and sudden cardiac death in patients with myocardial infarction and left ventricular systolic dysfunction who are in CHF and already being treated with a beta-blocker and an ACE inhibitor or Ang II blocker. Close monitoring of potassium levels and appropriate dosage adjustments or use of diuretics are necessary because a small percentage of patients taking eplerenone develop hyperkalemia.

Surgical Care

Kantrowitz initially described intraaortic balloon pumping (IABP) in 1953, but the procedure was first used clinically in 1969 in a patient with cardiogenic shock. Since the 1980s, IABP has been increasingly used in various clinical situations as a lifesaving intervention to obtain hemodynamic stabilization prior to definite therapy.

• Procedure
• • The intraaortic balloon pump is inserted percutaneously via the femoral artery using a modified Seldinger technique. The distal end of the pump is placed just distal to the aortic knob and the origin of left subclavian artery.
  • Fluoroscopy may be used for correct positioning of the balloon, and a subsequent chest radiograph should be obtained to document satisfactory balloon placement.
• Proper timing of IABP for optimal hemodynamic support
• • Proper timing of counterpulsation is necessary for maximum hemodynamic support. The timings of balloon inflation and deflation are best evaluated and adjusted at a pump frequency of 1:2.
  • Inflation of the balloon should occur in early diastole, just after aortic valve closure, and should correspond to the dicrotic notch of the aortic pressure waveform. Balloon deflation should occur in early systole, just before the aortic valve opens.
  • Proper inflation leads to an assisted peak diastolic pressure higher than the unassisted peak systolic arterial pressure. Proper deflation results in assisted aortic end-diastolic pressure approximately 10 mm Hg lower than the unassisted end-diastolic pressure.
  • Diastolic augmentation enhances perfusion of the coronary circulation and carotid arteries. The reduction in end-diastolic pressure decreases aortic impedance (afterload) and augments systole.
  • IABP reduces aortic impedance and systolic pressure, leading to a 15-25% reduction in LV wall stress. This level of afterload reduction improves LV volume, LV emptying, and myocardial oxygen consumption.
  • Diastolic aortic pressure augmentation enhances myocardial perfusion and coronary blood flow. The effects on coronary blood flow may be variable but generally range from a boost of 10-20% in ischemic territories.
  • IABP can decrease LV filling pressures by 20-25% and can improve cardiac output by 20% in patients with cardiogenic shock; therefore, IABP reduces myocardial oxygen demand significantly, although the beneficial effect of increased oxygen supply to the myocardium may also occur in some clinical situations.
• Indications for IABP
• • IABP is very effective in providing temporary support to patients in cardiogenic shock while definite therapies such as angioplasty or cardiac bypass surgery are undertaken. At most institutions, IABP is generally considered to be a bridge to a definite revascularization procedure or to implementation of an LV assist device.
  • IABP is effective in stabilizing patients with unstable angina refractory to medical therapy prior to a definitive revascularization procedure.
  • IABP may be a lifesaving intervention in patients with acute mitral regurgitation secondary to papillary muscle ischemia, infarction, and other causes such as infectious endocarditis or myxomatous degeneration. IABP reduces afterload (thereby reducing the severity of mitral regurgitation), enhances forward cardiac output, reduces left atrial pressure, and improves pulmonary edema.
  • IAPB is used to stabilize patients, which allows time to plan the definitive surgical procedure in patients who are hemodynamically unstable.
  • IABP could also provide hemodynamic support in the perioperative and postoperative period.
• Contraindications and complications
  • The absolute contraindications for IABP counterpulsation are aortic dissection, severe aortic regurgitation, presence of a large arteriovenous shunt, and severe coagulopathy.
  • The relative contraindications are severe peripheral vascular disease, recent thrombolytic therapy, and bleeding diathesis.
  • IABP can cause several complications that should be monitored while the patient is maintained on IABP support. Generally, a mild reduction in platelet counts occurs; however, these usually do not fall below 100,000/µL
  • Complications may occur during cannulation of the femoral artery and include perforation, laceration, or dissection of the artery (1-6%). Thrombosis of the iliofemoral artery and distal emboli may also occur (1-7%), and limb ischemia has been reported in up to 40% of patients. The limb ischemia is reversible upon removing the intraaortic balloon pump unless thrombosis has developed, which requires embolectomy to save the limb.
  • The other complications are localized bleeding (3-5%), infection (2-4%), thrombocytopenia ( <1%), and intestinal ischemia ( <1%).
• Ventricular assist device: This is generally considered a short-term therapy (eg, acute myocarditis) or bridge to transplant, though a recent study suggested improved survival when used long term.
• Biventricular pacing (cardiac resynchronization): A new therapy, biventricular pacing may improve left ventricular pumping efficacy in patients with relatively severe cardiomyopathy and wide QRS complex.
• Cardiac transplantation

Consultations

Consultation with subspecialists depends on the underlying cause of CHF. Heart failure is now an area of subspecialization within cardiology.

• If the acute episode is attributed to an acute myocardial infarction, acute cardiac ischemia, or acute dysrhythmia, consultation with a cardiologist is warranted.
• If the episode is attributed to fluid overload in patients with renal failure, consultation with a nephrologist is indicated for emergent/urgent hemodialysis.
• If heart failure results from acute valvular dysfunction, consultation with a cardiothoracic surgeon and a cardiologist for urgent valve replacement may be indicated, depending on the integrity of the valve involved.
• In patients who develop cardiogenic shock, consultation with a cardiologist is generally indicated in order to rapidly diagnose and aggressively treat with various modalities (pharmacologic and/or mechanical), to maximize cardiac performance and improve hemodynamics, and, in some cases, to place an intraaortic balloon pump to serve as a temporizing measure prior to surgery (ie, for valve replacement or coronary revascularization).

Diet

Patients admitted with heart failure or pulmonary edema should maintain a low-salt diet in order to minimize fluid overload. Monitor fluid balance closely.

Activity

• Patients with decompensated heart failure should be placed on complete bed rest until their decompensation is resolved. This is necessary to maximally reduce myocardial oxygen demand and to avoid exacerbation of the abnormal hemodynamics and symptoms of heart failure.
• Once the patient with heart failure has been stabilized, activity should be gradually and progressively increased. Emphasize the importance of cardiac rehabilitation to all patients with heart failure who require improved cardiac fitness. Encourage patients to exercise daily for at least 20-30 minutes in a low-intensity, endurance-enhancing activity such as walking, biking, or swimming. Regular exercise improves the quality of life for these patients and improves efficiency of oxygen utilization at the tissue level, thus reducing the workload of the heart in the role of oxygen delivery to end organs and muscles.

 

MEDICATION

The goals of pharmacotherapy are to reduce morbidity and to prevent complications.

Drug Category: Human B-type natriuretic peptides (hBNPs)

Dilate veins and arteries. Used in the treatment of acute severe CHF.

Drug Name
Nesiritide (Natrecor)

Description
Recombinant DNA form of hBNP, which dilates veins and arteries. hBNP binds to particulate guanylate cyclase receptor of vascular smooth muscle and endothelial cells. Binding to receptor causes increase in cGMP, which serves as second messenger to dilate veins and arteries. Reduces PCWP and improves dyspnea in patients with acutely decompensated CHF.

Adult Dose
2 mcg/kg IV bolus over 60 sec; follow by 0.01 mcg/kg/min continuous infusion; bolus volume (mL) = 0.33 X patient weight (kg); infusion flow rate of bolus (mL/h) = 0.1 X patient weight (kg)

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; systolic blood pressure <90 mm Hg; patients suspected of having or known to have low cardiac filling pressures, severe aortic or mitral stenosis, restrictive or obstructive cardiomyopathy, constrictive pericarditis, pericardial tamponade, conditions in which cardiac output is dependent upon venous return

Interactions
Concurrent administration with ACE inhibitors and other vasodilators may cause hypotension

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Do not initiate at dose higher than recommended; may affect renal function in patients whose renal function may depend on activity of RAAS; may cause hypotension (administer in settings where blood pressure can be monitored closely); discontinue drug if hypotension develops; VT, nonsustained VT, headache, abdominal pain, back pain, insomnia, anxiety, angina pectoris, nausea, and vomiting may occur

Drug Category: Diuretics

May improve symptoms of venous congestion through elimination of retained fluid and preload reduction. Used in CHF. Help counteract the sodium and water retention caused by activation of the RAAS.

Drug Name
Furosemide (Lasix); Bumetanide (Bumex); Torsemide (Demadex)

Description
Increase excretion of water by interfering with chloride-binding cotransport system, which in turn inhibits sodium and chloride reabsorption in ascending loop of Henle and distal renal tubule. Bumetanide does not appear to act in the distal renal tubule. Dose must be individualized to patient. Depending on response, administer at small dose increments until desired diuresis occurs.

Adult Dose
Furosemide: 20-80 mg/d PO/IV/IM; titrate up to 600 mg/d for severe edematous states; depending on response, administer at increments of 20-40 mg no sooner than 6-8 h after previous dose

Bumetanide: 0.5-2 mg/dose PO 1-2 times/d; titrate dose upward until desired diuretic effect reached; not to exceed 10 mg/d; alternatively, 0.5-1 mg/dose IV/IM; not to exceed 10 mg/d

Torsemide: 10-20 mg PO/IV qd; not to exceed 200 mg/d; titrate dose upward by approximately doubling the dose until desired diuretic effect reached; doses >200 mg/d not adequately studied

Pediatric Dose
Furosemide: 1-2 mg/kg/dose PO; not to exceed 6 mg/kg/dose; not to administer more frequently than q6h
Bumetanide: Not established
Torsemide: Not established

Contraindications
Documented hypersensitivity; hepatic coma, anuria, increasing anuria, and state of severe electrolyte depletion

Interactions
Potential for salicylate toxicity in patients on high doses of salicylates and loop diuretics significant (salicylates and loop diuretics compete for secretion by renal tubules); NSAIDs may decrease efficacy of loop diuretics; loop diuretics increase potential for lithium toxicity; simultaneous use of loop diuretics and cholestyramine not recommended as cholestyramine decreases absorption of loop diuretics; probenecid decreases effect loop diuretics; coadministration with aminoglycosides may increase ototoxicity; enzyme inducers, including phenytoin, carbamazepine, and phenobarbital, may reduce efficacy of loop diuretics; hypotensive effects of ACE inhibitors may increase when administered concomitantly with loop diuretics; arrhythmias may occur in patients taking digoxin if diuretic-induced electrolyte disturbances occur

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Torsemide is pregnancy category B; perform frequent serum electrolyte, CO₂, glucose, creatinine, uric acid, calcium, and BUN determinations during first few months of therapy and periodically thereafter; profound diuresis with fluid and electrolyte loss may occur; caution in hepatic failure

Drug Name
Spironolactone (Aldactone)

Description
For management of edema resulting from excessive aldosterone excretion. Competes with aldosterone for receptor sites in distal renal tubules, increasing water excretion while retaining potassium and hydrogen ions.

Adult Dose
25-200 mg/d PO qd or divided bid

Pediatric Dose
1.5-3.5 mg/kg/d PO qd or divided qid

Contraindications
Documented hypersensitivity; anuria, renal failure, hyperkalemia

Interactions
May decrease effect of anticoagulants; potassium and potassium-sparing diuretics may increase toxicity of spironolactone

Pregnancy
D - Unsafe in pregnancy

Precautions
Caution in renal and hepatic impairment

Drug Category: Angiotensin receptor blockers

Interfere with the binding of formed Ang II to its endogenous receptor. Used primarily when patients are intolerant of ACE inhibitors because of adverse effects but are gaining wider use as first-line vasodilator agents. Equally effective as ACE inhibitors.

Drug Name
Losartan (Cozaar); Candesartan (Atacand); Valsartan (Diovan)

Description
Block the vasoconstrictor and aldosterone-secreting effects of Ang II. May induce more complete inhibition of RAAS than ACE inhibitors, do not affect response to BK, and are less likely to be associated with cough and angioedema. For patients unable to tolerate ACE inhibitors.

Adult Dose
Losartan: 25-100 mg PO qd/bid
Candesartan: 8-16 mg/d PO initially; not to exceed 32 mg/d
Valsartan: 80 mg/d PO; may increase to 160 mg/d if needed

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity

Interactions
Ketoconazole, sulfaphenazole, and phenobarbital may decrease effects; cimetidine may increase effects of losartan and candesartan

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Category D in second and third trimesters of pregnancy; caution in renal impairment (serum creatinine >3.5), severe aortic stenosis, unilateral or bilateral renal artery stenosis or severe CHF; watch for serum potassium

Drug Category: ACE inhibitors

Inhibit renal systemic and tissue generation of Ang II by ACE; decrease metabolism of bradykinin (BK). Their blockade of Ang II and the delayed clearance of BK by ACE blocks the direct vasoconstriction of Ang II, as well as the activation of the sympathetic nervous system, and promotes arterial and venous dilation. In addition, ACE inhibitors reduce intracavitary pressures and diminish Wass stress, thereby decreasing myocardial oxygen demand. They inhibit the release of aldosterone, thereby reducing intravascular volume and preload. Among vasodilators, the ACE inhibitors are the most balanced vasodilators, having an equal effect on reducing both afterload and preload.

Drug Name
Captopril (Capoten); Enalapril (Vasotec); Quinapril (Accupril)

Description
Lisinopril (Prinivil, Zestril); Ramipril (Altace); Fosinopril (Monopril)--Prevent conversion of Ang I to Ang II (a potent vasoconstrictor), resulting in increased levels of plasma renin and a reduction in aldosterone secretion.

Adult Dose
Captopril: 6.25-12.5 mg PO tid; not to exceed 150 mg tid
Enalapril: 2.5-5 mg/d PO (increase as necessary); dosing range: 10-40 mg/d PO in 1-2 divided doses; alternatively, 1.25 mg/dose IV over 5 min q6h
Quinapril: 10 mg PO qd
Lisinopril: 10 mg/d PO qd or divided bid; increase by 5-10 mg/d at 1- to 2-wk intervals; not to exceed 80 mg/d
Ramipril: 2.5 mg PO bid initially; titrate up to 5 mg bid when possible
Fosinopril: 10 mg/d PO initially; may increase to 20-40 mg/d qd or divided bid

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; renal impairment, angioedema

Interactions
NSAIDs may reduce hypotensive effects of ACE inhibitors; ACE inhibitors may increase digoxin, lithium, and allopurinol levels; rifampin decreases ACE inhibitor levels; probenecid may increase ACE inhibitor levels; hypotensive effects of ACE inhibitors may be enhanced when concurrently administered with diuretics

Pregnancy
D - Unsafe in pregnancy

Precautions
Category D in second and third trimester of pregnancy; caution in renal impairment, valvular stenosis, or severe CHF

Drug Category: Vasodilators

The use of a vasodilators reduces SVR, thus allowing more forward flow and improving cardiac output. Indicated for CHF.

Drug Name
Nitroglycerin (Nitrostat, Deponit, Transderm-Nitro Patch)

Description
Isosorbide dinitrate (Isordil), Isosorbide mononitrate (Imdur)--First-line therapy for patients who are not hypotensive. Provides excellent and reliable preload reduction. Higher doses provide mild afterload reduction. Has rapid onset and offset (both within minutes), allowing rapid clinical effects and rapid discontinuation of effects in adverse clinical situations.

Adult Dose
Nitroglycerin
Topical: Apply topically 1/2-2" q6h
Transdermal: 0.3-0.6 mg/h qd
Intravenous: 0.2-10 mcg/kg/min IV infusion; titrate by 10 mcg/min increments until desired hemodynamic effect achieved or until maximally tolerated dose reached
Spray: Single spray (0.4 mg), which is equivalent to single 1/150 sublingual; dose may be repeated q3-5min as hemodynamics permit, up to maximum of 1.2 mg
Isosorbide dinitrate: 10-80 mg PO bid/qid
Isosorbide mononitrate: 30-90 PO mg qd

Pediatric Dose
Not established

Contraindications
Documented sensitivity; hypotension; severe anemia; shock; postural hypotension; head trauma; closed-angle glaucoma; cerebral hemorrhage

Interactions
Sildenafil (Viagra) taken within 24 h may induce precipitous and potentially lethal decreases in blood pressure; aspirin may increase nitrate serum concentrations; marked symptomatic orthostatic hypotension may occur with coadministration of calcium channel blockers (dose adjustment of either agent may be necessary)

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Extreme caution in right ventricle infarction because of importance of adequate preload in maintaining cardiac output; caution in patients with severe aortic stenosis because of needed adequate preload to maintain cardiac output

Drug Name
Hydralazine (Apresoline)

Description
Decreases systemic resistance through direct vasodilation of arterioles.

Adult Dose
10-25 mg PO tid/qid initially; adjust dose based on individual response; typical dose range is 200-600 mg PO qd in 2-4 divided doses

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; mitral valve rheumatic heart disease

Interactions
MAOIs and beta-blockers may increase hydralazine toxicity; pharmacologic effects of hydralazine may be decreased by indomethacin

Pregnancy
B - Usually safe but benefits must outweigh the risks.

Precautions
Hydralazine has been implicated in myocardial infarction; caution in suspected coronary artery disease

Drug Name
Isosorbide dinitrate and hydralazine (BiDil)

Description
Fixed-dose combination of isosorbide dinitrate (20 mg/tab), a vasodilator with effects on both arteries and veins, and hydralazine (37.5 mg/tab), a predominantly arterial vasodilator. Indicated for heart failure in black patients, based in part on results from the African American Heart Failure Trial. Two previous trials in the general population of patients with severe heart failure found no benefit but suggested a benefit in black patients. Compared with placebo, black patients showed a 43% reduction in mortality rate, a 39% decrease in hospitalization rate, and a decrease in symptoms from heart failure.

Adult Dose
1 tab PO tid; may titrate upward, not to exceed 2 tab tid

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; allergy to organic nitrates

Interactions
Hydralazine may increase propranolol, metoprolol, and lisinopril AUC and C_max; isosorbide dinitrate may cause additive vasodilating effects with other vasodilators (eg, sildenafil [Viagra], vardenafil [Levitra]), especially when coadministered with alcohol

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
May cause symptomatic hypotension even with small doses; careful hemodynamic monitoring required if administered in patients with acute MI
Hydralazine: May cause SLE-like symptoms, including glomerulonephritis, tachycardia, hypotension, and peripheral neuritis (pyridoxine therapy may be required)
Isosorbide dinitrate: If hypotension exists, may aggravate angina associated with hypertrophic cardiomyopathy

Drug Name
Nitroprusside (Nitropress)

Description
Produces vasodilation and increases inotropic activity of the heart. At higher dosages, may exacerbate myocardial ischemia by increasing heart rate.

Adult Dose
Begin infusion at 0.3-0.5 mcg/kg/min IV and use increments of 0.5 mcg/kg/min; titrate to desired effect; average dose is 1-6 mcg/kg/min
Infusion rates >10 mcg/kg/min IV may lead to cyanide toxicity

Pediatric Dose
Administer as in adults

Contraindications
Documented hypersensitivity; subaortic stenosis, decreased cerebral perfusion, arteriovenous shunt or coarctation of aorta (eg, compensatory hypertension); relatively contraindicated in atrial fibrillation or flutter with rapid ventricular rate

Interactions
Effects are additive when administered with other hypotensive agents

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Caution in increased intracranial pressure, hepatic failure, severe renal impairment, and hypothyroidism; in renal or hepatic insufficiency, nitroprusside levels may increase and can cause cyanide toxicity; sodium nitroprusside has ability to lower blood pressure and thus should be used only in those patients with mean arterial pressures >70 mm Hg

Drug Category: Inotropic agents

Augment both coronary and cerebral blood flow present during the low flow states. Used in severe acute CHF with low cardiac output.

Drug Name
Digoxin (Lanoxin, Lanoxicaps)

Description
Cardiac glycoside with direct inotropic effects in addition to indirect effects on cardiovascular system. Acts directly on cardiac muscle, increasing myocardial systolic contractions. Indirect actions result in increased carotid sinus nerve activity and enhanced sympathetic withdrawal for any given increase in mean arterial pressure.

Adult Dose
0.125-0.375 mg PO qd

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; beriberi heart disease, idiopathic hypertrophic subaortic stenosis, constrictive pericarditis, and carotid sinus syndrome

Interactions
IV calcium may produce arrhythmias in digitalized patients; medications that may increase digoxin levels include alprazolam, benzodiazepines, bepridil, captopril, cyclosporine, propafenone, propantheline, quinidine, diltiazem, aminoglycosides, oral amiodarone, anticholinergics, diphenoxylate, erythromycin, felodipine, flecainide, hydroxychloroquine, itraconazole, nifedipine, omeprazole, quinine, ibuprofen, indomethacin, esmolol, tetracycline, tolbutamide, and verapamil; medications that may decrease serum digoxin levels include aminoglutethimide, antihistamines, cholestyramine, neomycin, penicillamine, aminoglycosides, oral colestipol, hydantoins, hypoglycemic agents, antineoplastic treatment combinations (including carmustine, bleomycin, methotrexate, cytarabine, doxorubicin, cyclophosphamide, vincristine, procarbazine), aluminum or magnesium antacids, rifampin, sucralfate, sulfasalazine, barbiturates, kaolin/pectin, and aminosalicylic acid

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Hypokalemia may reduce positive inotropic effect of digitalis; hypercalcemia predisposes patient to digitalis toxicity, and hypocalcemia can make digoxin ineffective until serum calcium levels are normal; magnesium replacement therapy must be instituted in patients with hypomagnesemia to prevent digitalis toxicity; patients diagnosed with incomplete AV block may progress to complete block when treated with digoxin; exercise caution in hypothyroidism, hypoxia, and acute myocarditis; adjust dose in renal impairment; highly toxic (overdoses can be fatal)

Drug Name
Dobutamine (Dobutrex)

Description
Produces vasodilation and increases inotropic state. At higher dosages may cause increased heart rate, exacerbating myocardial ischemia.

Adult Dose
0.5 mcg/kg/min IV initially; titrate until desired therapeutic effect attained

Pediatric Dose
Administer as in adults

Contraindications
Documented hypersensitivity; idiopathic hypertrophic subaortic stenosis and atrial fibrillation or flutter

Interactions
Beta-adrenergic blockers antagonize effects of dobutamine; general anesthetics may increase toxicity

Pregnancy
B - Usually safe but benefits must outweigh the risks.

Precautions
Following a myocardial infarction use with extreme caution; hypovolemic state should be corrected before using this drug

Drug Name
Dopamine (Intropin)

Description
Naturally occurring catecholamine that acts as a precursor to NE. Stimulates both adrenergic and dopaminergic receptors. Hemodynamic effect is dose-dependent. Low-dose use is associated with dilation within renal and splanchnic vasculature, resulting in enhanced diuresis. Moderate doses enhance cardiac contractility and heart rate. Higher doses cause increased afterload through peripheral vasoconstriction.
Administer by continuous IV infusion. Usually used in severe heart failure. Reserved for patients with moderate hypotension (eg, systolic blood pressure 70-90 mm Hg). Typically, moderate or higher doses used.

Adult Dose
5 mcg/kg/min IV continuous infusion initially; titrate to blood pressure stabilization; not to exceed 20 mcg/kg/min

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; pheochromocytoma; ventricular fibrillation; obstructive hypertrophic cardiomyopathy

Interactions
Phenytoin, alpha- and beta-adrenergic blockers, general anesthesia, and MAOIs increase and prolong effects of dopamine

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Monitor urine flow, cardiac output, pulmonary wedge pressure, and blood pressure closely during infusion; prior to infusion, correct hypovolemia with either whole blood or plasma as indicated; monitoring central venous pressure or LV filling pressure may be helpful in detecting and treating hypovolemia; 10- to 20-mcg/kg/min doses increase levels of peripheral vasoconstriction and afterload; may increase tachyarrhythmias and cause greater myocardial oxygen consumption and cardiac ischemia; alkaline solutions may inactivate dopamine if administered through same IV line

Drug Name
Norepinephrine (Levophed)

Description
Naturally occurring catecholamine with potent alpha-receptor and mild beta-receptor activity. Stimulates beta1- and alpha-adrenergic receptors, resulting in increased cardiac muscle contractility, heart rate, and vasoconstriction. Increases blood pressure and afterload. Increased afterload may result in decreased cardiac output, increased myocardial oxygen demand, and cardiac ischemia. Generally reserved for use in patients with severe hypotension (eg, systolic blood pressure <70 mm Hg) or hypotension unresponsive to other medication.

Adult Dose
0.5-1 mcg/min IV infusion initially, titrated to effect; not to exceed 30 mcg/min

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; obstructive hypertrophic cardiomyopathy; peripheral or mesenteric vascular thrombosis because ischemia may be increased and area of infarct extended

Interactions
Enhances pressor response of NE by blocking reflex bradycardia caused by NE

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
May cause tachyarrhythmia (especially sinus tachycardia), increased myocardial oxygen demand, and cardiac ischemia; alkaline solutions may inactivate NE if administered through same IV line; extravasation may cause severe tissue necrosis, (administer into a large vein); if extravasation occurs, immediately infiltrate 5-10 mg of phentolamine (diluted in 10-15 mL of isotonic sodium chloride solution) to prevent necrosis; caution in occlusive vascular disease; if possible, correct blood-volume depletion before administration

Drug Category: Phosphodiesterase enzyme inhibitors

Inhibition of type III cAMP phosphodiesterase(s) and other mechanisms. Bipyridine-positive inotropic agents and vasodilators with little chronotropic activity. Different from both digitalis glycosides and catecholamines in mode of action. These agents are balanced vasodilators, having equal reduction in both afterload and preload, to same degree as ACE inhibitors.

Drug Name
Milrinone (Primacor), Amrinone (Inocor)

Description
Milrinone: Positive inotropic agent and vasodilator. Results in reduced afterload, reduced preload, and increased cardiac output. Several studies comparing milrinone to dobutamine have demonstrated that milrinone showed greater improvements in preload and afterload and improvements in cardiac output, without significant increases in myocardial oxygen consumption.

Amrinone: Produces vasodilation and increases inotropic state. More likely to cause tachycardia than dobutamine; may exacerbate myocardial ischemia.

Adult Dose
Milrinone: 50 mcg/kg IV loading dose over 10 min, followed by continuous infusion at 0.25-1.0 mcg/kg/min; titrate to maintain adequate systolic blood pressure and cardiac output

Amrinone: 0.75 mg/kg IV bolus slowly over 2-3 min; maintenance infusion is 5.0-10 mcg/kg/min; not to exceed 10 mg/kg; adjust dose according to patient response; not to exceed 10 mg/kg

Pediatric Dose
Milrinone: Not established

Amrinone: Administer as in adults

Contraindications
Milrinone: Documented hypersensitivity; obstructive hypertrophic cardiomyopathy

Amrinone: Documented hypersensitivity

Interactions
Milrinone: Precipitates in presence of furosemide

Amrinone: Coadministration with diuretics may result in hypovolemia and decrease in filling pressure; cardiac glycosides have additive effects on amrinone

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Milrinone: Monitor fluids, electrolyte changes, and renal function during therapy; excessive diuresis may increase potassium loss and predispose digitalized patients to arrhythmias (correct hypokalemia with potassium supplementation prior to treatment); slow rates or stop infusion in patients showing excessive decreases in blood pressure; previous vigorous diuretic therapy has caused significant decreases in cardiac filling pressure; administer cautiously and monitor blood pressure, heart rate, and clinical symptomatology

Amrinone: Discontinue therapy if symptoms of liver toxicity develop; correct hypokalemic states before administering therapy

Drug Category: Beta-adrenergic blockers

Inhibit chronotropic, inotropic, and vasodilatory responses to beta-adrenergic stimulation. Particularly useful in the patient with elevated blood pressure and relative tachycardia. Inhibits sympathetic nervous stimulation, particularly E and NE and blocks alpha1-adrenergic vasoconstrictor activity. Has moderate afterload reduction properties and results in slight preload reduction as well.

Drug Name
Carvedilol (Coreg)

Description
Nonselective beta- and alpha1-adrenergic blocker. Does not appear to have intrinsic sympathomimetic activity. May reduce cardiac output and decrease peripheral vascular resistance.

Adult Dose
3.125 mg PO bid; maintain for 1-2 wk if tolerated and double dose q1-4wk to maximally tolerated dose or to maximum of 50 mg bid

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; hypotension; bradycardia; AV/SA node disease; cardiogenic shock; overt cardiac failure

Interactions
Rifampin, barbiturates, cholestyramine, colestipol, NSAIDs, salicylates, and penicillins may decrease effects; carvedilol may increase effects of antidiabetic agents, digoxin, and calcium channel blockers; concurrent administration with clonidine may increase blood pressure and decrease heart rate; carvedilol may decrease effect of sulfonylureas; cimetidine, fluoxetine, paroxetine, and propafenone may increase carvedilol levels

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Caution in CHF being treated with digitalis, diuretics, or ACE inhibitors (AV conduction may be slowed); discontinue if liver impairment occurs; caution in peripheral vascular disease, hyperthyroidism, and diabetes mellitus

Drug Name
Metoprolol XL (Toprol)

Description
Selective beta1-adrenergic blocker at lower doses; inhibits beta2-receptors at higher doses. Does not have intrinsic sympathomimetic activity. May reduce cardiac output, but does not appear to decrease peripheral vascular resistance to any significant degree.

Adult Dose
100 mg PO qd; titrate to maximum dose of 400 mg/d PO in 1-2 divided doses.

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; hypotension; bradycardia; AV/SA node disease; cardiogenic shock; overt cardiac failure

Interactions
Rifampin, barbiturates, cholestyramine, colestipol, NSAIDs, salicylates, and penicillins may decrease effects; high doses of metoprolol XL may increase effects of antidiabetic agents, digoxin, and calcium-channel blockers because of beta2-receptor inhibition; concurrent administration with clonidine may increase blood pressure and decrease heart rate; metoprolol XL may decrease effect of sulfonylureas; cimetidine, fluoxetine, paroxetine, and propafenone may increase levels

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Caution in CHF being treated with digitalis, diuretics, or ACE inhibitors (AV conduction may be slowed); discontinue if liver impairment occurs; caution in peripheral vascular disease (at higher doses) and hyperthyroidism

 

FOLLOW-UP

Further Inpatient Care

• After the patient has been initially stabilized and the decompensation of heart failure has been resolved, further inpatient care depends on the underlying cause of CHF.
• Place patients with heart failure in a monitored bed to watch for acute dysrhythmias. Pay strict attention to the patient's fluid balance by closely monitoring fluid input and output. Maintain patients who are fluid-overloaded in negative fluid balance through the use of diuretics, or, if necessary in patients with renal failure, hemodialysis with ultrafiltration.
• Check cardiac enzymes to evaluate for myocardial infarction. Slight elevations in cardiac enzymes can occur with decompensated heart failure in the absence of myocardial infarction because of coronary thrombosis.
• Perform coronary angiography on patients whose decompensated heart failure resulted from an acute coronary syndrome, either unstable angina or myocardial infarction. Stress testing can also be performed later during hospitalization to evaluate for reversible ischemia in patients without acute coronary syndromes but who have prior symptoms of angina or who have a high likelihood of coronary artery disease as the cause of LV dysfunction.
• Order echocardiography at the earliest possible moment to evaluate for evidence of acute valvular dysfunction and wall motion abnormalities and to assess the patient's systolic and diastolic function. Since the long-term therapy of patients with heart failure differs significantly between those with predominantly systolic dysfunction and those with predominantly diastolic dysfunction, it is absolutely essential that all patients with heart failure have echocardiographic evaluation of cardiac function, chamber size, and valve function.
• In most patients with decompensated heart failure, oral vasodilator therapy, most commonly ACE inhibitors, can be used as first-line therapy to reverse the cardiac decompensation and to restore optimal cardiac function. The clinician must be extremely cautious with vasodilator therapy only in patients with severe aortic or mitral stenosis or in those with obstructive cardiomyopathy. Patients who required intravenous inotropic support should be weaned off as quickly as possible and should have their vasodilator therapy maximized quickly in order to avoid the risk of adverse cardiac events from increased myocardial oxygen consumption leading to ischemia.
• Patients in whom pulmonary edema was caused by dietary factors or medication noncompliance need strict counseling and education to help prevent recurrence.

Further Outpatient Care

• Focus further outpatient care of patients with heart failure on maximizing some or all of the medical modalities used in their treatment. Undertake further assessment of the clinical and hemodynamic effects of that therapy fairly soon after discharge and at regular intervals.
• Precise definition and aggressive treatment of all reversible causes for heart failure is absolutely essential. For instance, patients with myocardial ischemia (particularly those with reduced systolic function) should be promptly evaluated with noninvasive and/or invasive evaluations of coronary perfusion, and they should be promptly referred for revascularization if they are suitable candidates for such revascularization. Similarly, patients with severe valvular disease, assessed clinically and echocardiographically, should be promptly referred for cardiac catheterization. If a patient is a suitable candidate for valve replacement or repair, he or she should undergo prompt surgical therapy.
• Patients with nonreversible NYHA class IV heart failure who are younger than 65 years and facing the likely prospect of death within the next 6-24 months, despite maximal medical therapy, and who are not candidates for beneficial surgical therapy, should be promptly referred to a cardiac transplant center for consideration of cardiac transplantation.
• Screen patients with cardiomyopathy and heart failure for candidacy for cardioverter/defibrillator implantation because the risk of sudden death in these patients is considerable.

In/Out Patient Meds

• See Treatment and Medications.

Transfer

• Transfer of patients to a tertiary receiving hospital generally is indicated if the presenting hospital lacks adequate resources to care for such patients. Most patients with heart failure can be well managed at community hospitals. However, if the cause of heart failure is determined to require definitive surgery for stabilization, transfer is often indicated. Note the following examples:
• • Patients with heart failure that develops as a result of acute valvular dysfunction requiring urgent valve replacement may require transfer to a tertiary care facility that performs open heart surgery.
  • Patients with acute myocardial infarction resulting in cardiogenic shock hypotension may require transfer for emergency PTCA or CABGS. Thrombolysis may be attempted at the presenting hospital, but outcome is generally poor without angioplasty or CABGS.
  • Patients with severe heart failure with hemodynamic complications should be transferred from presenting hospitals that lack sufficient resources for, or experience with, managing patients with heart failure who require complex inotropic support or hemodialysis.
  • Patients with NYHA class IV heart failure who are younger than 65 years and facing the likely prospect of death within the next 6-12 months, despite maximal medical therapy, and who are not candidates for coronary revascularization, should be transferred to a cardiac transplant center for consideration of cardiac transplantation if they cannot be stabilized enough to be discharged home on maximal medical and mechanical therapy.

Complications

• The major complications associated with heart failure are sudden cardiac death from ventricular tachyarrhythmias or bradyarrhythmias and pump failure with cardiovascular collapse. Approximately half of patients with heart failure eventually die from fatal ventricular arrhythmias. Prompt diagnosis and treatment usually prevent this complication in the acute setting. Prompt diagnosis of CHF and prompt treatment to reduce pulmonary venous congestion, reduce afterload, and improve cardiac output is essential in preventing cardiovascular and respiratory failure.

Prognosis

• In general, the inpatient mortality rate for patients with heart failure is 5-20%.
• Heart failure associated with acute myocardial infarction is associated with an inpatient mortality rate of 20-40%; mortality approaches 80% in patients who are also hypotensive (eg, cardiogenic shock).

Patient Education

• To help prevent recurrence, counsel and educate patients in whom heart failure was caused by dietary factors or medication noncompliance with regard to the importance of proper diet and the necessity of medication compliance.
• For excellent patient education resources, visit eMedicine's Heart Center, Cholesterol Center, Diabetes Center. Also, see eMedicine's patient education articles Congestive Heart Failure, High Cholesterol, Chest Pain, Heart Rhythm Disorders, Coronary Heart Disease, and Heart Attack.
• REFERENCES
• http://www.emedicine.com/med/topic3552.htm