Improved Survival With an Implanted Defibrillator in Patients With Coronary Disease at High Risk for Ventricular Arrhythmia (N Engl J Med. 1996;335:1933-1940). Moss AJ, Hall WJ, Cannom DS, Daubert JP, Higgins SL, Klein H, Levine JH, Saksena S, Waldo AL, Wilber D, Brown MW, Heo M, for the Multicenter Automatic Defibrillator Implantation Trial Investigators.
Moss and colleagues, for the Multicenter Automatic Defibrillator Implantation Trial (MADIT) Investigators, studied whether prophylactic therapy with an implanted cardioverter-defibrillator, as compared with conventional medical therapy, improves survival in patients with unsustained ventricular tachycardia, prior myocardial infarction, and left ventricular dysfunction. During a course of 5 years, 196 patients in New York Heart Association functional class I, II, or III with prior myocardial infarction, a left ventricular ejection fraction ≤0.35, a documented episode of asymptomatic unsustained ventricular tachyarrhythmia, and inducible nonsuppressible ventricular arrhythmia on electrophysiological study were randomly assigned to receive either an implantable defibrillator (n=95) or conventional therapy (n=101). The investigators used a two-sided sequential design with death from any cause as the end point. Baseline clinical characteristics of the two treatment groups were similar.
During an average follow-up of 27 months, there were 15 deaths in the patients who had a defibrillator implanted (11 from cardiac causes) and 39 deaths in the conventional treatment group (27 from cardiac causes) (Figure). Although the number of patients treated was relatively small, there was no clear evidence that other antiarrhythmic therapy had a significant influence in prolonging survival.
Thus, in this study, patients with a prior myocardial infarction and with left ventricular dysfunction at high risk for ventricular tachyarrhythmia had their survival prolonged by the prophylactic placement of an implanted defibrillator.
The vertical axis is a measure of the accumulated differences in survival between the two treatments presented as a log-rank statistic. The horizontal axis is the variance of the log-rank statistic and is related to the number of deaths. The upper stopping boundary indicates defibrillator efficacy and the lower boundary indicates defibrillator inefficacy or no difference between treatments. Reproduced with the permission of the New England Journal of Medicine.
- Copyright © 1997 by American Heart Association