title: ECG quantification of myocardial scar does not differ between primary and secondary prevention ICD recipients with ischemic heart disease.
abstract: BACKGROUND
  Myocardial scar is an anatomic substrate for potentially lethal arrhythmias. Recent study showed that higher QRS-estimated scar size using the Selvester QRS score was associated with increased arrhythmogenesis during electrophysiologic testing. Therefore, QRS scoring might play a potential role in risk stratification before implantable cardioverter defibrillator (ICD) implantation. In this study, we tested the hypothesis that QRS scores among ICD recipients for secondary prevention are higher than QRS scores in primary prevention patients.
  
  
  RESULTS
  From the hospital database, 100 consecutive patients with ischemic heart disease and prior ICD implantation were selected. Twelve-lead electrocardiograms (ECGs) had been obtained before implantation. ECGs were scored following the 32-points Selvester QRS scoring system and corrected for underlying conduction defects and/or hypertrophy. Ninety-three ECGs were suitable for scoring; seven ECGs were rejected because of noise, missing leads, excessive ventricular extrasystoles, or ventricular pacing. No statistically significant difference in QRS score was found between the primary [6.90 (standard deviation [SD] 3.94), n = 63] and secondary prevention group [6.17 (SD 4.50) (P = 0.260), n = 30]. Left ventricular ejection fraction (LVEF) was significantly higher in the secondary prevention group [31% (SD 13.5) vs 24% (SD 11.7) (P = 0.015)]. When patients with LVEF > or =35% were excluded, QRS scores were still comparable, namely 7.02 (SD 4.04) in the primary prevention group (n = 52) and 6.28 (SD 4.24) in the secondary (P = 0.510) (n = 18).
  
  
  CONCLUSIONS
  We found no significant difference in QRS score between the ischemic primary and secondary prevention groups. Therefore, a role of the Selvester QRS score as a risk stratifier remains unlikely.
authors.affiliation: Department of Cardiology, Medisch Spectrum Twente, Haaksbergerstraat 55, Enschede, The Netherlands. k.kraaier@mst.nl
authors.forename: Karin
authors.initials: K
authors.lastname: Kraaier
authors.forename: Pascal F H M
authors.initials: PF
authors.lastname: van Dessel
authors.forename: Job
authors.initials: J
authors.lastname: van der Palen
authors.forename: Arthur A M
authors.initials: AA
authors.lastname: Wilde
authors.forename: Marcoen F
authors.initials: MF
authors.lastname: Scholten
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000503:physiopathology / Q000628:therapy; D002921:Cicatrix / Q000503:physiopathology*; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000503:physiopathology* / Q000517:prevention & control*; D011446:Prospective Studies; D012307:Risk Factors; D055502:Secondary Prevention; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology / Q000628:therapy