Pharmacologic treatment of dilated cardiomyopathy with special reference to the role of beta-blockers.

The pharmacologic treatment of dilated cardiomyopathy encompasses measures such as temporary administration of amino acids and calories for those who may be undernourished and avoidance of drugs such as alcohol, nicotine, amphetamines and high doses of tricyclic antidepressants. Anticoagulants should be used in patients with persistent failure or marked dilatation of the cardiac chambers since about 20% suffer from major embolic complications. In patients with ventricular tachycardia, R-on-T, or multifocal ventricular ectopic beats, class I antiarrhythmic drugs, or if unsuccessful, amiodarone should be administered since the risk of sudden death is substantial. In addition to digitalis and diuretics, the use of vasodilators is generally accepted to be of clinical value for reduction of symptoms in heart failure. Reports concerned with long-term clinical and hemodynamic effects with drugs such as prazosin, captopril and the combination of hydralazine and isosorbide dinitrate are conflicting and, so far, there is no evidence that any vasodilator prolongs survival. The beta-agonists, such as prenalterol, are limited in their usefulness by tachycardia induction, a tendency to provoke serious arrhythmias, tremor and anxiety as well as hemodynamic tolerance development. While the noncatecholamine inotropics such as milrinone may provide symptomatic relief in severe congestive heart failure, they also increase heart rate, induce ventricular arrhythmias and are associated with high one-year mortality rates. The beneficial effect of long-term beta-blockade, which we first reported in 1975 to include a decrease in functional class, increase in exercise tolerance, improvement in physical findings, increase in ejection fraction and enhanced survival, has been met with scepticism.(ABSTRACT TRUNCATED AT 250 WORDS)