MORTALITY FOLLOWING VENTRICULAR ARRHYTHMIA SUPPRESSION BY ENCAINIDE, FLECAINIDE, AND MORICIZINE AFTER MYOCARDIAL-INFARCTION - THE ORIGINAL DESIGN CONCEPT OF THE CARDIAC-ARRHYTHMIA SUPPRESSION TRIAL (CAST)

Objective.-To test the hypothesis that in survivors of myocardial infa rction, the suppression of ventricular premature depolarizations impro ves survival free of cardiac arrest and arrhythmic death. Design.-Inte rnational, prospective, multicenter, randomized, placebo-controlled tr ial. Setting.-University and community hospitals. Patients.-A total of 3549 patients with myocardial infarction and left ventricular dysfunc tion. Intervention.-Administration of encainide, flecainide, moricizin e, or placebo to suppress ventricular premature depolarizations. Main Outcome Measures.-Overall survival and survival free of cardiac arrest or arrhythmic death were compared in patients randomized to long-term , active antiarrhythmic drug therapy vs corresponding placebo, using t he stratified log rank statistic. Results.-At 1 year from the time of randomization to blinded therapy, 95% of placebo-treated patients vs 9 0% of active drug-treated patients remained alive (P=.0006). Similarly , at 1 year, 96% of placebo-treated patients vs 93% of active drug-tre ated patients remained free of cardiac arrest or arrhythmic death (P=. 003). Conclusions.-The suppression of asymptomatic or mildly symptomat ic ventricular arrhythmias after myocardial infarction does not improv e survival and can increase mortality. Treatment strategies designed s olely to suppress these arrhythmias should no longer be followed.