title: Magnetic resonance estimates of the extent and heterogeneity of scar tissue in ICD patients with ischemic cardiomyopathy predict ventricular arrhythmia.
abstract: BACKGROUND
  The majority of patients receiving implantable cardioverter-defibrillator (ICD) implantation under current guidelines never develop sustained ventricular arrhythmia; therefore, better markers of risk for sustained ventricular tachycardia and/or ventricular fibrillation are needed.
  
  
  OBJECTIVE
  The purpose of this study was to identify cardiac magnetic resonance arrhythmic risk predictors of ischemic cardiomyopathy before ICD implantation.
  
  
  METHODS
  Forty-three subjects (mean age, 64.5 ± 11.9 years) with previous myocardial infarction who were referred for ICD implantation were evaluated by cardiac magnetic resonance imaging (MRI). The MRI protocol included left ventricular functional parameter assessment using steady-state free precession and late gadolinium enhancement MRI using inversion recovery fast gradient echo. Left ventricular functional parameters were measured using cardiac magnetic resonance software. Subjects were followed up for 6-46 months, and the events of appropriate ICD treatments (shocks and antitachycardia pacing) were recorded.
  
  
  RESULTS
  Twenty-eight patients experienced 46 spontaneous episodes during a median follow-up duration of 30 months. The total myocardial infarct (MI) size (18.05 ± 11.44 g vs 38.83 ± 19.87 g; P = .0006), MI core (11.63 ± 7.14 g vs 24.12 ± 12.73 g; P = .0002), and infarct gray zone (6.43 ± 4.64 g vs 14.71 ± 7.65 g; P = .0004) were significantly larger in subjects who received appropriate ICD therapy than in those who did not experience an episode of ventricular tachycardia and/or ventricular fibrillation. Multivariate regression analyses for the infarct gray zone and MI core adjusted for New York Heart Association class, diabetes, and etiology (primary or secondary prevention) revealed that the gray zone and MI core were predictors of appropriate ICD therapies (P = .0018 and P = .007, respectively).
  
  
  CONCLUSIONS
  The extent of MI scar may predict which patients would benefit most from ICD implantation.
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada. Electronic address: Dr.Tawfiq.ZeidanShwiri@horizonnb.ca.
authors.forename: Tawfiq
authors.initials: T
authors.lastname: Zeidan-Shwiri
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
authors.forename: Yuesong
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
authors.forename: Ilan
authors.initials: I
authors.lastname: Lashevsky
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
authors.forename: Ehud
authors.initials: E
authors.lastname: Kadmon
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
authors.forename: Darren
authors.initials: D
authors.lastname: Kagal
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
authors.forename: Alexander
authors.initials: A
authors.lastname: Dick
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
authors.forename: Avishag
authors.initials: A
authors.lastname: Laish Farkash
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
authors.forename: Gideon
authors.initials: G
authors.lastname: Paul
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
authors.forename: Donsheng
authors.initials: D
authors.lastname: Gao
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Shurrab
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Newman
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
authors.forename: Graham
authors.initials: G
authors.lastname: Wright
authors.affiliation: Arrhythmia Services, Schulich Heart Centre, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
authors.forename: Eugene
authors.initials: E
authors.lastname: Crystal
mesh_terms: D000368:Aged; D002170:Canada; D009202:Cardiomyopathies / Q000175:diagnosis / Q000209:etiology / Q000473:pathology / Q000628:therapy; D002921:Cicatrix / Q000175:diagnosis / Q000209:etiology; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications*; D009206:Myocardium / Q000473:pathology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D018570:Risk Assessment / Q000379:methods; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control
keywords: Cardiac magnetic resonance imaging; Gray zone; Implantable cardioverter-defibrillator; Infarct core; Ventricular fibrillation; Ventricular tachycardia