Effectiveness of implantable defibrillators for preventing arrhythmic events and death: a meta-analysis.

Abstract Objectives The aim of this study was to compare the effectiveness of the implantable cardioverter defibrillator (ICD) and medical strategies for prevention of arrhythmic events and death. Background The ICD is a potential strategy to reduce mortality in patients at risk of sudden death. Methods The MEDLINE, EMBASE, and Cochrane Library electronic databases were searched from January 1966 to April 2002. All published randomized controlled trials comparing ICD implantation with medical therapy were reviewed. Four independent reviewers extracted data on all-cause mortality, nonarrhythmic death, and arrhythmic death using a standardized protocol. Results Nine studies including over 5,000 patients were synthesized using both fixed-effects and random-effects models. The primary and secondary prevention trials showed a significant benefit of the ICD with respect to arrhythmic death, with relative risks (RR) of 0.34 and 0.50, respectively (both p Conclusions Although the ICD decreases the risk of arrhythmic death, its impact on all-cause mortality is related to the underlying risk of arrhythmia-related death relative to competing causes. Given the cost of the device strategy, policies of targeted intervention based on the future risk of arrhythmia are warranted.