Clinical Question: Do implantable defibrillators reduce mortality in patients with nonischemic cardiomyopathy?

Setting: Various (meta-analysis)

Study Design: Meta-analysis (randomized controlled trials)

Synopsis: Investigators thoroughly searched multiple databases using evidence-based sources including MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials. Inclusion criteria identified only prospective randomized controlled trials of implantable defibrillators versus medical therapy in patients with nonischemic cardiomyopathy. The trials reported all-cause mortality. From an initial 675 articles of potential relevance, eight met the inclusion criteria (with a total of 2,146 patients). Of these, five were primary prevention trials enrolling 1,854 patients with nonischemic cardiomyopathy. The authors did not state specifically whether the individual studies were evaluated independently by more than one person.

Overall, mortality was reduced significantly among patients randomized to an implantable defibrillator versus medical therapy (relative risk = 0.69; 95 percent confidence interval, 0.55 to 0.87). The findings from the various studies were similar (homogeneous) and there was no evidence of significant publication bias. Implantable defibrillators did not decrease mortality following a myocardial infarction (Hohnloser SH, et al. Prophylactic use of an implantable cardioverter-defibrillator after acute myocardial infarction. N Engl J Med December 9, 2004;351:2481–8).

Bottom Line: In addition to standard medical therapy, implantable defibrillators further reduce mortality in selected patients with nonischemic cardiomyopathy. (Level of Evidence: 1a–)