title: Early Implantation of Primary Prevention Implantable Cardioverter Defibrillators for Patients with Newly Diagnosed Severe Nonischemic Cardiomyopathy.
abstract: BACKGROUND
  Primary prevention implantable cardioverter defibrillators (ICDs) reduce mortality in selected patients with severe systolic dysfunction. Current guidelines suggest a 3- to 6-month waiting period before implantation.
  
  
  METHODS
  We retrospectively studied 29 consecutive patients with newly diagnosed nonischemic cardiomyopathy (NICM) who underwent primary prevention ICD implantation within 6 months of diagnosis between January 2008 and April 2014. Cardiac MRI (CMR) evaluated left ventricular ejection fraction (LVEF) and regional fibrosis preimplant. The primary end point was "failure to qualify for an ICD at 12 months postimplant," either due to LVEF ≥ 35% or deterioration necessitating mechanical support or transplantation, without appropriate ICD therapy. Secondary end points were appropriate and inappropriate ICD therapy.
  
  
  RESULTS
  Baseline mean age was 44.2 ± 14.8 years and median LVEF 16.4%. Median time from diagnosis to implant was 32 days. At 12 months, 17 patients (58.6%) no longer qualified for an ICD, mainly due to LVEF improvement. At follow-up (mean 32.0 ± 20.6 months), three patients received appropriate therapy (one for ventricular fibrillation). All three had CMR late gadolinium enhancement (LGE) and nonsustained ventricular tachycardia (NSVT) preimplant. Cardiac resynchronization at implant predicted LVEF improvement.
  
  
  CONCLUSIONS
  Early appropriate therapy, particularly for ventricular fibrillation, is infrequent for patients with very severe NICM who have ICDs implanted within 6 months of diagnosis. The majority of these patients would not qualify for an ICD at 12 months postinsertion. In the absence of a multimodality risk score, early ICD insertion should only be considered in selected cases (presence of LGE and NSVT). Wearable cardioverter defibrillators may have a role as a bridge to ICD decision.
authors.affiliation: Department of Cardiology, Alfred Hospital, Melbourne, Victoria, Australia. alex.voskoboinik@gmail.com.
authors.forename: Aleksandr
authors.initials: A
authors.lastname: Voskoboinik
authors.affiliation: Department of Cardiology, Alfred Hospital, Melbourne, Victoria, Australia.
authors.forename: Jason
authors.initials: J
authors.lastname: Bloom
authors.affiliation: Department of Cardiology, Alfred Hospital, Melbourne, Victoria, Australia.|Baker IDI Heart & Diabetes Research Institute, Melbourne, Victoria, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Taylor
authors.affiliation: Department of Cardiology, Alfred Hospital, Melbourne, Victoria, Australia.|Department of Cardiology, St. Vincent's Hospital, Melbourne, Victoria, Australia.
authors.forename: Justin
authors.initials: J
authors.lastname: Mariani
mesh_terms: D000328:Adult; D009202:Cardiomyopathies / Q000175:diagnosis* / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008297:Male; D011322:Primary Prevention / Q000379:methods*; D019919:Prosthesis Implantation / Q000379:methods; D012189:Retrospective Studies; D055502:Secondary Prevention / Q000379:methods*; D016896:Treatment Outcome
keywords: arrhythmia; cardiomyopathy; cardioverter defibrillator; sudden death