The changing syndrome of heart failure

EPIDEMIOLOGY: Risk factors for heart failure vary in magnitude, depending on age and sex. Incidence, prevalence, morbidity and mortality are strongly age-related. The presence of hypertension or diabetes among men aged 35-64 years increases the risk fourfold. Electrocardiographic evidence of left ventricular hypertrophy in this group increases the risk 15-fold, independently of the presence of hypertension. Other independent risks include obesity, a high ratio of total to high-density cholesterol, proteinuria, an intraventricular conduction delay or a non-specific repolarization abnormality. Among blacks, the presence of hypertension increases the incidence of heart failure; among whites, the underlying cause is more commonly ischemic heart disease. PATHOPHYSIOLOGY: Impaired cardiac contractility is the primary hemodynamic change in heart failure. Increases in ventricular filling pressure following changes in ventricular diastolic compliance contribute to the symptoms. Neurohormonal changes, particularly those related to activation of the renin-angiotensin-aldosterone system through interactions with the sympathetic nervous system, have been correlated with the severity of the disease and mortality. Drugs that modulate neurohormonal systems have more favorable effects on the outcome of heart disease than those that only affect hemodynamic systems. THERAPY: Patients must be educated towards improved compliance with recommendations on sodium intake, cessation of smoking, weight control, exercise and medication regimens. Current drug therapy includes treatment with diuretics with or without digitalis and can be improved by the use of angiotensin converting enzyme (ACE) inhibitors. Optimal doses of these inhibitors, their use in patients with asymptomatic left ventricular dysfunction and their mechanisms of action are currently being evaluated.