title: Infarct morphology identifies patients with substrate for sustained ventricular tachycardia.
abstract: OBJECTIVE
  We sought to evaluate whether infarct size characterization by cardiac magnetic resonance imaging (MRI) is a better predictor of inducible ventricular tachycardia (VT) than left ventricular ejection fraction (LVEF).
  
  
  BACKGROUND
  Inducibility of VT at electrophysiologic study (EPS) and low LVEF can identify patients with a substrate for VT. Magnetic resonance imaging has been shown to identify, with high precision, areas of myocardial infarction and may therefore be a better tool to evaluate for a substrate for VT.
  
  
  METHODS
  We studied 48 patients with known coronary artery disease who were referred for EPS using cine and gadolinium-enhanced MRI. Wall motion and infarct characteristics were determined blindly and compared among patients with no inducible ventricular arrhythmias (n = 21), those with inducible monomorphic VT (MVT, n = 18), and those with either inducible polymorphic VT or ventricular fibrillation (n = 9).
  
  
  RESULTS
  Patients with MVT had larger infarcts than patients who did not have inducible arrhythmias (mass: 49 +/- 5 g [SE] vs. 28 +/- 5 g, p < 0.005; surface area: 172 +/- 15 cm(2) vs. 93 +/- 14 cm(2), p < 0.0005). Patients with polymorphic VT/fibrillation had intermediate values (mass: 36 +/- 7 g; surface area: 115 +/- 22 cm(2)). Ejection fraction was inversely related to infarct mass and surface area, with R(2) values ranging from 0.21 to 0.27. Logistic regression and receiver-operating characteristic analysis demonstrated that infarct mass and surface area were better predictors of inducibility of MVT than LVEF.
  
  
  CONCLUSIONS
  Infarct surface area and mass, as measured by cardiac MRI, are better identifiers of patients who have a substrate for MVT than LVEF. Further evaluation of infarct size characterization by cardiac MRI as a predictor of sudden cardiac death is warranted.
authors.affiliation: Department of Medicine, Divisions of Cardiology and Radiology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, USA.
authors.forename: David
authors.initials: D
authors.lastname: Bello
authors.forename: David S
authors.initials: DS
authors.lastname: Fieno
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Kim
authors.forename: F Scott
authors.initials: FS
authors.lastname: Pereles
authors.forename: Rod
authors.initials: R
authors.lastname: Passman
authors.forename: Gina
authors.initials: G
authors.lastname: Song
authors.forename: Alan H
authors.initials: AH
authors.lastname: Kadish
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Goldberger
mesh_terms: D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D011237:Predictive Value of Tests; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013318:Stroke Volume; D017180:Tachycardia, Ventricular / Q000150:complications / Q000473:pathology* / Q000503:physiopathology