Heart Failure: A Review

The most common cause of heart failure is left ventricular systolic dysfunction (about 60% of patients). Currently, 5 million Americans are afflicted with heart failure, approximately 2% of the population. 1 Patients with heart failure account for about 1 million hospital admissions annually, with another 2 million patients having heart failure as a secondary diagnosis. One third of these patients are readmitted within 90 days for recurrent decompensation

Patients at high risk for developing heart failure are those with hypertension, coronary artery disease, diabetes mellitus, familial history of cardiomyopathy, use of cardiotoxins, and obesity.

Initially, as a direct result of inadequate cardiac output and systemic perfusion, the body activates several neurohormonal pathways to increase circulating blood volume. The sympathetic nervous system increases heart rate and contractility, both of which increase cardiac output. Circulating catecholamines also cause arteriolar vasoconstriction in nonessential vascular beds and stimulate secretion of renin from the juxtaglomerular apparatus of the kidney.

Table 1: American College of Cardiology–American Heart Association Classification of Chronic Heart Failure

Stage / Description
A—high risk for developing heart failure / Hypertension, diabetes mellitus, CAD, family history of cardiomyopathy
B—asymptomatic heart failure / Previous MI, LV dysfunction, valvular heart disease
C—symptomatic heart failure / Structural heart disease, dyspnea and fatigue, impaired exercise tolerance
D—refractory end-stage heart failure / Marked symptoms at rest despite maximal medical therapy

Signs and symptomsThere is a wide spectrum of potential clinical manifestations of heart failure. Most patients have signs and symptoms of fluid overload and pulmonary congestion, including dyspnea, orthopnea, and paroxysmal nocturnal dyspnea. Patients with right ventricular failure have jugular venous distention, peripheral edema, hepatosplenomegaly, and ascites. Others, however, do not have congestive symptoms but have signs and symptoms of low cardiac output, including fatigue, effort intolerance, cachexia, and renal hypoperfusion. The NYHA functional classification scheme is used to assess the severity of functional limitations and correlates fairly well with prognosis

Table 2: New York Heart Association (NYHA) Heart Failure Symptom Classification System

NYHA Class / Level of Impairment
I / No symptom limitation with ordinary physical activity
II / Ordinary physical activity somewhat limited by dyspnea (e.g., long-distance walking, climbing two flights of stairs)
III / Exercise limited by dyspnea with moderate workload (e.g., short-distance walking, climbing one flight of stairs)
IV / Dyspnea at rest or with very little exertion

On physical examination, patients with heart failure may be tachycardic and tachypneic, with bilateral inspiratory rales, jugular venous distention, and edema. They often are pale and diaphoretic. The first heart sound usually is relatively soft if the patient is not tachycardic. An S3 will be present.

Diagnosis

Electrocardiogram, chest radiograph, and B-type natriuretic peptide assay.

The single most useful diagnostic test is the echocardiogram, which can distinguish between systolic and diastolic dysfunction.

A useful diagnostic test for the detection of heart failure is the B-type natriuretic peptide (BNP) assayBNP levels correlate with severity of heart failure and decrease as a patient reaches a compensated state. This blood test may be useful for distinguishing heart failure from pulmonary disease. Because smokers often have both these clinical diagnoses, differentiating between them may be challenging.

Summary

* Jugular venous distention is a useful physical sign of heart failure.

* The lungs usually are clear in chronic heart failure.

* The BNP assay improves the accuracy of diagnosing heart failure.

* Echocardiography is the single most useful diagnostic modality.

* Coronary angiography confirms or excludes coronary artery disease as the cause.

Treatment

Lifestyle Modifications

Dietary sodium and fluid restrictions should be implemented in all patients with congestive heart failure. Limiting patients to 2 g/day of dietary sodium and 2 L/day of fluid will lessen congestion and lower the need for diuretics. Patient education guidelines are listed below:

Patient Education Guidelines

·  2-g sodium diet

·  Monitoring weight daily

·  2-L fluid restriction

·  Monitoring blood pressure

·  Medications

·  Smoking cessation

·  Light aerobic exercise

·  Knowing who to call

·  Achieving ideal weight

·  Follow-up visits

Drugs:

Angiotensin-Converting Enzyme Inhibitors

Angiotensin Receptor Blockers

Beta Blockers

Digoxin

Diuretics

·  All heart failure patients should receive an ACE inhibitor and a beta blocker.

·  Diuretics are needed in most patients to manage fluid retention.

·  Digoxin is reserved for patients with signs and symptoms of heart failure.

·  Aldosterone antagonists are used in patients with Class III or IV heart failure.

·  ARBs or a hydralazine plus nitrate may be added to standard therapy for additional benefit.

1