Efficacy of beta blockers in idiopathic dilated cardiomyopathy and ischemic cardiomyopathy.

Despite the well-documented benefits of beta blockade in a variety of cardiovascular conditions, the value of beta blockade in congestive heart failure (CHF) is still in question. The concept of neurohormonal blockade in heart failure has, however, brought beta blockade into focus. There is experimental evidence for the value of blocking sympathetic activation in CHF, and increased sympathetic activation may be an etiologic factor for development of CHF. Clinical studies have shown that long-term beta blockade improves both systolic and diastolic function. The effects on exercise tolerance and quality of life seem to differ between beta1-selective and nonselective beta blockers in favor of the beta1-selective blockers. To date, results of all trials reveal a consistent pattern of decreased cardiovascular morbidity. In one trial of metoprolol, fewer heart transplantations were required; such a reduction may have a great impact on healthcare costs associated with heart failure. Improved long-term survival found by one study must be confirmed in additional trials: 3 such survival trials (with metoprolol, bisoprolol, and bucindolol) are now in progress.