title: Myocardial fibrosis predicts appropriate device therapy in patients with implantable cardioverter-defibrillators for primary prevention of sudden cardiac death.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the association between regional myocardial fibrosis and ventricular arrhythmias in patients with cardiomyopathy.
  
  
  BACKGROUND
  Patients with heart failure are at risk of sudden cardiac death (SCD). Current guidelines recommend implantable cardioverter-defibrillator (ICD) devices for a subgroup based on impaired left ventricular function. A significant proportion of devices never discharge, hence a more accurate method for targeting those at risk is desirable.
  
  
  METHODS
  We prospectively enrolled 103 patients meeting criteria for ICD implantation for primary prevention of SCD. Cardiac magnetic resonance imaging was performed before device implantation. Regional fibrosis was identified with late gadolinium enhancement (LGE).
  
  
  RESULTS
  Median follow-up was 573 days (interquartile range: 379 to 863 days). The LGE identified regional fibrosis in 31 of 61 (51%) patients with nonischemic cardiomyopathy (NICM) and in all 42 patients with ischemic cardiomyopathy (ICM). There was a 29% (9 of 31) discharge rate in the NICM group with LGE compared with a 14% (6 of 42) discharge rate in the ICM group (p = NS). There were no ICD discharges in the NICM group without LGE, which was significantly lower than the rate observed in both the ICM patients (p = 0.04) and the NICM patients with LGE (p < 0.01). Left ventricular ejection fraction was similar in patients with and without device therapy (24 ± 12% vs. 26 ± 8%, p = NS) and those with or without LGE (25 ± 9% vs. 26 ± 9%, p = NS).
  
  
  CONCLUSIONS
  Patients with advanced cardiomyopathy and myocardial fibrosis demonstrated by LGE on cardiac magnetic resonance imaging have a high likelihood of appropriate ICD therapy. Correspondingly, absence of LGE may indicate a lower risk for malignant ventricular arrhythmias.
authors.affiliation: Alfred Hospital and Baker IDI Heart and Diabetes Research Institute, Melbourne, Australia.
authors.forename: Leah
authors.initials: L
authors.lastname: Iles
authors.forename: Heinz
authors.initials: H
authors.lastname: Pfluger
authors.forename: Lisa
authors.initials: L
authors.lastname: Lefkovits
authors.forename: Michelle J
authors.initials: MJ
authors.lastname: Butler
authors.forename: Peter M
authors.initials: PM
authors.lastname: Kistler
authors.forename: David M
authors.initials: DM
authors.lastname: Kaye
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Taylor
mesh_terms: D009202:Cardiomyopathies / Q000473:pathology*; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D005260:Female; D005355:Fibrosis; D005500:Follow-Up Studies; D006333:Heart Failure / Q000628:therapy*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D011446:Prospective Studies; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis