Amiodarone in patients with congestive heart failure and asymptomatic ventricular arrhythmia. Survival Trial of Antiarrhythmic Therapy in Congestive Heart Failure

Abstract

Background: Asymptomatic ventricular arrhythmias in patients with congestive heart failure are associated with increased rates of overall mortality and sudden death. Amiodarone is now used widely to prevent ventricular tachycardia and fibrillation. We conducted a trial to determine whether amiodarone can reduce overall mortality in patients with congestive heart failure and asymptomatic ventricular arrhythmias.

Methods: We used a double-blind, placebo-controlled protocol in which 674 patients with symptoms of congestive heart failure, cardiac enlargement, 10 or more premature ventricular contractions per hour, and a left ventricular ejection fraction of 40 percent or less were randomly assigned to receive amiodarone (336 patients) or placebo (338 patients). The primary end point was overall mortality, and the median follow-up was 45 months (range, 0 to 54).

Results: There was no significant difference in overall mortality between the two treatment groups (P = 0.6). The two-year actuarial survival rate was 69.4 percent (95 percent confidence interval, 64.2 to 74.6) for the patients in the amiodarone group and 70.8 percent (95 percent confidence interval, 65.7 to 75.9) for those in the placebo group. At two years, the rate of sudden death was 15 percent in the amiodarone group and 19 percent in the placebo group (P = 0.43). There was a trend toward a reduction in overall mortality among the patients with nonischemic cardiomyopathy who received amiodarone (P = 0.07). Amiodarone was significantly more effective in suppressing ventricular arrhythmias and increased the left ventricular ejection fraction by 42 percent at two years.

Conclusions: Although amiodarone was effective in suppressing ventricular arrhythmias and improving ventricular function, it did not reduce the incidence of sudden death or prolong survival among patients with heart failure, except for a trend toward reduced mortality among those with nonischemic cardiomyopathy.