title: Implantable cardioverter defibrillators for primary prevention in patients with nonischemic cardiomyopathy: A systematic review and meta-analysis.
abstract: BACKGROUND
  Implantable cardioverter defibrillators (ICDs) have proved their favorable outcomes on survival in selected patients with cardiomyopathy. Although previous meta-analyses have shown benefit for their use in primary prevention, the evidence remains less robust for patients with nonischemic cardiomyopathy (NICM) in comparison to patients with coronary artery disease (CAD).
  
  
  OBJECTIVE
  To evaluate the effect of ICD therapy on reducing all-cause mortality and sudden cardiac death (SCD) in patients with NICM.
  
  
  METHODS
  PubMed (1993-2016), the Cochrane Central Register of Controlled Trials (2000-2016), reference lists of relevant articles, and previous meta-analyses. Search terms included defibrillator, heart failure, cardiomyopathy, randomized controlled trials, and clinical trials.
  
  
  METHODS
  Eligible trials were randomized controlled trials with at least an arm of ICD, an arm of medical therapy and enrolled some patients with NICM. The primary endpoint in the trials should include all-cause mortality or mortality from SCD.
  
  
  METHODS
  Hazard ratios (HRs) for all-cause mortality and mortality from SCD were either extracted or calculated along with their standard errors.
  
  
  RESULTS
  Of the 1047 abstracts retained by the initial screen, eight randomized controlled trials were identified. Five of these trials reported relevant data regarding patients with NICM and were subsequently included in this meta-analysis. Pooled analysis of HRs suggested a statistically significant reduction in all-cause mortality among a total of 2573 patients randomized to ICD vs medical therapy (HR 0.80; 95% CI, 0.67-0.96; P=.02). Pooled analysis of HRs for mortality from SCD was also statistically significant (n=1677) (HR 0.51; 95% CI, 0.34-0.76; P=.001).
  
  
  CONCLUSIONS
  ICD implantation is beneficial in terms of all-cause mortality and mortality from SCD in certain subgroups of patients with NICM.
authors.affiliation: Department of Internal Medicine, Staten Island University Hospital, Staten Island, NY, USA.
authors.forename: Tamer
authors.identifier: http://orcid.org/0000-0002-5632-5571
authors.initials: T
authors.lastname: Akel
authors.affiliation: Department of Cardiology, Staten Island University Hospital, Staten Island, NY, USA.
authors.forename: James
authors.initials: J
authors.lastname: Lafferty
mesh_terms: D000328:Adult; D000368:Aged; D009202:Cardiomyopathies / Q000150:complications / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D016757:Death, Sudden, Cardiac / Q000209:etiology / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011322:Primary Prevention / Q000295:instrumentation* / Q000379:methods; D011474:Prosthesis Design; D016032:Randomized Controlled Trials as Topic; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome
keywords: Cardiomyopathy; Cardioverter; Defibrillator; Heart failure; ICD; Nonischemic