IMPROVED SURVIVAL WITH AN IMPLANTED DEFIBRILLATOR IN PATIENTS WITH CORONARY-DISEASE AT HIGH-RISK FOR VENTRICULAR ARRHYTHMIA

Background Unsustained ventricular tachycardia in patients with previo us myocardial infarction and left ventricular dysfunction is associate d with a two-year mortality rate of about 30 percent. We studied. whet her prophylactic therapy with an implanted cardioverter-defibrillator, as compared with conventional medical therapy, would improve survival in this high-risk group of patients. Methods Over the course of five years, 196 patients in New York Heart Association functional class I, II, or III with prior myocardial infarction; a left ventricular ejecti on fraction less than or equal to 0.35; a documented episode of asympt omatic unsustained ventricular tachycardia; and inducible, nonsuppress ible ventricular tachyarrhythmia on electrophysiologic study were rand omly assigned to receive an implanted defibrillator (n=95) or conventi onal medical therapy (n=101). We used a two-sided sequential design wi th death from any cause as the end point. Results The base-line charac teristics of the two treatment groups were similar. During an average follow-up of 27 months, there were 15 deaths in the defibrillator grou p (11 from cardiac causes) and 39 deaths in the conventional-therapy g roup (27 from cardiac causes) (hazard ratio for overall mortality, 0.4 6; 95 percent confidence interval, 0.26 to 0.82; P=0.009). There was n o evidence that amiodarone, beta-blockers, or any other antiarrhythmic therapy had a significant influence on the observed hazard ratio. Con clusions In patients with a prior myocardial infarction who are at hig h risk for ventricular tachyarrhythmia, prophylactic therapy with an i mplanted defibrillator leads to improved survival as compared with con ventional medical therapy. (C) 1996, Massachusetts Medical Society.