Effect of elapsed time from coronary revascularization to implantation of a cardioverter defibrillator on long-term survival in the MADIT-II trial.

INTRODUCTION: Coronary revascularization (CR) may reduce arrhythmia risk and improve long-term outcome in patients with left ventricular dysfunction. This study was designed to evaluate the effect of elapsed time from CR on long-term mortality and arrhythmic risk among patients who receive an implantable cardioverter defibrillator (ICD).

METHODS AND RESULTS: We evaluated the risk of 8-year mortality by elapsed time from CR to ICD implantation (categorized as: no CR; recent CR [<2 years]; or nonrecent CR [≥2 years], and assessed as a continuous measure) among 720 ICD recipients enrolled in the Multicenter Automatic Defibrillator Trial-II. At 8 years of follow-up, patients who did not undergo CR and those who underwent nonrecent CR had significantly higher mortality rates than patients who underwent recent CR (54%, 54%, and 36%, respectively; P < 0.001). Multivariate analysis demonstrated that no- and nonrecent CR were associated with respective 48% (P = 0.022) and 67% (P < 0.001) increases in mortality risk compared with recent CR. Assessment of time from CR as a continuous measure showed that every year elapsed from CR was associated with an adjusted 6% increase in 8-year mortality (P < 0.001), and in respective 6% (P < 0.001) and 6% (P = 0.003) increased risk for in-trial appropriate ICD therapy of ventricular tachyarrhythmias and appropriate ICD shocks.

CONCLUSIONS: We observed a direct relationship between elapsed time from CR and long-term mortality following ICD implantation. The favorable long-term effect on outcome of recent CR may be related to a time-dependent effect of CR on ventricular arrhythmic burden and the need for appropriate ICD shocks.