Mortality Effect of ICD in Primary Prevention of Nonischemic Cardiomyopathy: A Meta-Analysis of Randomized Controlled Trials

Introduction: Implantation of an implantable cardioverter defibrillator (ICD) for primary prevention of sudden cardiac death (SCD) is controversial in view of the recent DANISH trial which suggested no benefit with ICD for primary prevention in patients with non-ischemic cardiomyopathy (NICMP). Methods: We conducted a meta-analysis of randomized control trials studying the role of ICD in primary prevention of SCD in patients with NICMP. Only six studies were identified after the application of inclusion/exclusion criteria. Results: Pooling of these randomized trials showed a statistically significant benefit of using ICDs in patients with NICMP [OR 0.76 (0.64 – 0.91), I² = 0%]. Sensitivity analysis did not show a statistically significant mortality benefit of ICD in NICMP in trials which had adequate beta blocker, ACE/ARB and aldosterone receptor blocker (ALD-RB) use [OR 0.70 (0.41, 1.19), I² = 70%]. Conclusion: The DANISH trial's failure to show mortality benefit may be due to the significant number of patients who had CRT. Our meta-analysis studied the independent effect of ICDs and showed them to be associated with net mortality benefits in patients who are not on optimal guideline directed medical therapy; especially the patients not on ALD-RB.