Beneficial effects of long-term diltiazem treatment in dilated cardiomyopathy.

There is increasing evidence that chronic enhanced exogenous or endogenous catecholamine stimulation in patients with dilated cardiomyopathy may worsen hemodynamic status and prognosis. The cause of this deterioration may lie in myocellular calcium accumulation and microcirculatory disorders. In a prospective study, the calcium channel antagonist diltiazem was given to 22 patients with dilated cardiomyopathy (60 to 90 mg three times daily) in addition to conventional therapy of digitalis, diuretics and vasodilators. Twenty-five patients received the conventional therapy and served as historical controls. Eight additional patients who were not originally included in this control group received adjunctive diltiazem treatment after initially receiving conventional therapy alone. The three patient groups were similar in all hemodynamic and anamnestic features. Only patients with reduced myofibrillar volume fraction on myocardial biopsy were included in the trial, because they could be expected to show hemodynamic deterioration. The mean survival time was 29 months in the control group, whereas no patient in the diltiazem group died over a mean follow-up period of 15.4 months (p less than 0.001). Mean left ventricular ejection fraction increased from 0.34 to 0.44 (p less than 0.001) and New York Heart Association functional class improved significantly in the diltiazem group and during the diltiazem period in the crossover patients, but deteriorated in the control group. The results suggest that adjunctive diltiazem treatment in dilated cardiomyopathy has beneficial effects on mortality, hemodynamics and symptoms.