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ESSENTIALS OF DIAGNOSIS
Left ventricular dysfunction by echocardiography
Dyspnea on exertion and fatigue are common, but paroxysmal nocturnal dyspnea, orthopnea, and peripheral edema are more diagnostic.
Third heart sound, displaced cardiac apex, jugular venous distension, hepatojugular reflux, rales, murmur, or peripheral edema.
Any electrocardiographic (ECG) abnormality, radiographic evidence of pulmonary venous congestion, cardiomegaly, or pleural effusion
Elevated B-type natriuretic peptide (BNP) or N-terminal pro-BNP levels
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GENERAL CONSIDERATIONS
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Increased survivorship after acute myocardial infarction (MI) and improved treatment of hypertension, valvular heart disease, and coronary artery disease (CAD) have led to a significant increase in the prevalence of heart failure in the United States. Overall prevalence of any heart failure diagnosis is estimated at 2.6% (2.7% in men; 1.7% in women) and increases with age. Asymptomatic left ventricular systolic dysfunction (LVSD) has been found to be as prevalent as symptomatic LVSD: 1.4% and 1.5%, respectively. In patients with clinical symptoms of heart failure, moderate or severe isolated diastolic dysfunction appears to be as common as systolic dysfunction, and systolic dysfunction appears to increase with the severity of diastolic dysfunction.
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As defined by the American Heart Association (AHA) and the American College of Cardiology (ACC), heart failure is “a complex clinical syndrome that can result from any structural or functional cardiac disorder that impairs the ability of the ventricle to fill with or eject blood.”As cardiac output decreases in response to the stresses placed on the myocardium (Table 21-1) activation of the sympathetic nervous and renin-angiotensin-aldosterone system occur. These neurohormonal adaptations help increase blood pressure for tissue perfusion and also increase blood volume to enhance preload, stroke volume, and cardiac output. These compensatory mechanisms, which increase afterload, also lead to further myocardial deterioration and worsening myocardial contractility.
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CAUSES OF CARDIAC FAILURE
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Coronary artery disease and diabetes mellitus are the leading causes of heart failure in the United States. It is estimated that 60–70% of patients having systolic heart failure have CAD as the underlying etiology. CAD is a substantial predictor of developing symptomatic heart failure with LVSD compared ...