Prophylactic use of the implantable cardioverter-defibrillator and its effect on the long-term survival, cardiovascular and sudden cardiac death in nonischemic cardiomyopathy patients-a systematic review and meta-analysis

Implantable cardioverter-defibrillator (ICD) has shown to reduce sudden cardiac death and overall mortality in patients with dilated cardiomyopathy. The recently published DANISH trial has shown conflicting outcomes on the long-term survival in patients with prophylactic implantation of ICD in Non-Ischemic Cardiomyopathy (NICM). Two independent reviewers searched MEDLINE, PUBMED, Ovid, CINAHL,, and Cochrane Registry for randomized control trials (RCT's) comparing ICD to medical treatment (MT). Six RCT's enrolling 3389 patients (ICD = 1554 and MT = 1835) were included for final analysis. The primary outcomes were mortality comparing ICD to MT, 231 vs 337 (OR = 0.74, CI = 0.62-0.90, p = 0.002, and I-2 = 0%) favoring ICD. On comparing to amiodarone only, there were 47 deaths in the ICD arm vs 71 deaths in amiodarone arm, (OR = 0.66, CI = 0.44-0.98, p = 0.04, I-2 0%), to placebo and usual care only (excluding amiodarone); there were 225 deaths in ICD patients compared to 266 in the placebo and usual care arm, (OR = 0.73, CI = 0.59-0.92, p = 0.007, I-2 = 15%). The results of our analysis from these six RCTs clearly support the ongoing benefit of prophylactic ICD implantation and support current recommendations for ICD implantation in NICM patients. More RCT's at a larger scale are needed to further elucidate benefits of both ICD and CRT-D in this post PARADIGM era where MT is at a pinnacle in reducing morbidity and mortality in heart failure patients.