title: Nontransmural scar detected by magnetic resonance imaging and origin of ventricular tachycardia in structural heart disease.
abstract: BACKGROUND
  Contrast-enhanced magnetic resonance imaging (CMR) identifies scar tissue as an area of delayed enhancement (DE). The scar region might be the substrate for ventricular tachycardia (VT). However, the relationship between the occurrence of VT and the characteristics of scar tissue has not been fully studied.
  
  
  METHODS
  CMR was performed in 34 patients with monomorphic, sustained VT and dilated cardiomyopathy (DCM, n = 18), ischemic cardiomyopathy (ICM, n = 10), or idiopathic VT (IVT, n = 6). The VT exit site was assessed by a detailed analysis of the QRS morphology, including bundle branch block type, limb lead polarity, and precordial R-wave transition. On CMR imaging, the transmural score of each of the 17 segments was assigned, using a computer-assisted, semiautomatic technique, to measure the DE areas. Segmental scars were classified as nontransmural when DE was 1-75% and transmural when DE was 76-100% of the left ventricular mass in each segment.
  
  
  RESULTS
  A scar was detected in all patients with DCM or ICM. Nontransmural scar tissue was often found at the VT exit site, in patients with DCM or ICM. In contrast, no scar was found in patients with IVT.
  
  
  CONCLUSIONS
  CMR clarified the characteristics and distribution of scar tissue in patients with structural heart disease, and the presence and location of scar tissue might predict the VT exit site in these patients.
authors.affiliation: Division of Cardiology, Gunma Prefectural Cardiovascular Center, Maebashi, Gunma, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Yokokawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tada
authors.forename: Keiko
authors.initials: K
authors.lastname: Koyama
authors.forename: Shigeto
authors.initials: S
authors.lastname: Naito
authors.forename: Shigeru
authors.initials: S
authors.lastname: Oshima
authors.forename: Koichi
authors.initials: K
authors.lastname: Taniguchi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018780:Body Surface Potential Mapping; D002921:Cicatrix / Q000150:complications* / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D017682:Myocardial Stunning / Q000150:complications* / Q000175:diagnosis*; D017180:Tachycardia, Ventricular / Q000150:complications* / Q000175:diagnosis*