title: Native QRS duration predicts the occurrence of arrhythmic events in ICD recipients.
abstract: OBJECTIVE
  Identification of implantable cardioverter/defibrillator (ICD) recipients at higher risk of future therapies may assist in pre-empting future shocks. Native QRS duration is an established predictor of overall mortality, but the role of this parameter as a clinical predictor of arrhythmic events warrants further investigation.
  
  
  RESULTS
  In an analysis of a single-centre, 13-year ICD implantation experience (1990-2002), multiple clinical parameters including QRS duration were analysed using a multiple logistic regression model. Of 562 patients followed for at least 1 year, 98 (17%) did not receive ICD therapies (event-free, group A). Comparisons were made with a randomly selected sample of 123 patients who received ICD therapies (arrhythmic events, group B). There were no significant differences in age, gender, frequency of coronary artery disease, and degree of left ventricular dysfunction. However, QRS duration was a significant determinant of arrhythmic events (> or =100 vs. <100 ms: adjusted OR 2.75, 95% CI 1.37-5.51; > or =120 vs. <120 ms: adjusted OR 1.77, 95% CI 0.97-3.23). QRS duration was also a predictor of overall mortality in the logistic regression models (> or =100 ms: adjusted OR 3.72, 95% CI 1.17-11.9; > or =120 ms: adjusted OR 3.09, 95% CI 1.39-6.85).
  
  
  CONCLUSIONS
  In this ICD population, consisting largely of secondary prevention ICD recipients, longer QRS duration predicted higher likelihood of arrhythmic events. Extent of QRS prolongation could guide the decision to initiate prophylactic anti-arrhythmic therapy in ICD patients.
authors.affiliation: Heart Rhythm Research Laboratory, Division of Cardiology, UHN-62, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
authors.forename: Eric C
authors.initials: EC
authors.lastname: Stecker
authors.forename: Mehdi
authors.initials: M
authors.lastname: Zargarian
authors.forename: Vivek
authors.initials: V
authors.lastname: Dogra
authors.forename: Benjamin T
authors.initials: BT
authors.lastname: John
authors.forename: Jack
authors.initials: J
authors.lastname: Kron
authors.forename: John H
authors.initials: JH
authors.lastname: McAnulty
authors.forename: Sumeet S
authors.initials: SS
authors.lastname: Chugh
mesh_terms: D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000517:prevention & control; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis