DILTIAZEM IMPROVES CARDIAC-FUNCTION AND EXERCISE CAPACITY IN PATIENTSWITH IDIOPATHIC DILATED CARDIOMYOPATHY - RESULTS OF THE DILTIAZEM IN DILATED CARDIOMYOPATHY TRIAL

Background Evidence is arising that calcium antagonists in idiopathic dilated cardiomyopathy (IDC) may have beneficial effects on virus-indu ced cardiopathology, alcohol toxicity, microcirculatory disorders, and impaired calcium cycling, all possibly involved in the pathogenesis o f the disease. Thus, the effect of adjunct diltiazem (60 to 90 mg TID) on standard treatment was investigated.Methods and Results The Diltia zem in Dilated Cardiomyopathy (DiDi) trial was a randomized, double-bl ind, placebo-controlled, multicenter trial of 186 patients (92 receivi ng diltiazem, 94 receiving placebo) with IDC diagnosed by coronary ang iography, catheterization of the left side of the heart, and a left ve ntricular ejection fraction of <0.50 (mean, 0.34 +/- 0.11). The effect of adjunct diltiazem treatment on transplanting listing free survival , hemodynamics, exercise capacity, and subjective status was investiga ted. During the 24-month study period, 33 patients dropped out of the study; 153 patients finished the study protocol. Twenty-seven patients died or had a listing for hearth transplantation: 16 in the placebo g roup and 11 in the diltiazem group. The transplant listing-free surviv al rate was 85% fur diltiazem and 80% for placebo recipients (P=.444). After 24 months, only diltiazem significantly increased cardiac index at rest (P=.01) and under a workload (P=.02), systolic and diastolic pressures (P=.003 and P=.004), stroke volume index (P=.003), and strok e work index (P=.000) and decreased both pulmonary artery pressure und er workload (P=.007) and heart rate (P=.001). Diltiazem also increased exercise capacity (P=.002) and subjective well-being (P=.01). Adverse reactions were minor and evenly distributed in both groups, except fo r an increase in the PQ interval in the diltiazem group. Conclusions I n patients with IDC, the adjunct therapy of diltiazem improves cardiac function, exercise capacity, and subjective status without deleteriou s effects on transplant listing-free survival.