title: The association of J wave and ventricular tachycardia before device implantation with device interventions for ventricular tachyarrhythmia.
abstract: BACKGROUND
  J wave is known to be associated with increased risk of life-threatening ventricular arrhythmias in both structural and nonstructural heart disease. A documented history of ventricular tachycardia (VT) is also a known predictor for future arrhythmic events. The purpose of this study is to investigate prognostic factors in ventricular tachyarrhythmias in patients with an implanted defibrillator.
  
  
  METHODS
  Intracardiac electrograms were thoroughly analyzed in patients with either an implanted implantable cardioverter-defibrillator or with cardiac resynchronization therapy with a defibrillator. The relation between the clinical characteristics and the device interventions for ventricular tachyarrhythmias was evaluated retrospectively with multivariate Cox proportional hazards models.
  
  
  RESULTS
  This study enrolled a total of 160 patients who were followed for a mean period of 44 ± 28 months. Of these patients, 31 (19%) showed J wave and 77 (48%) showed documented VT before the device implantation. Multivariate Cox proportional hazards models revealed that the presence of J wave and the documented history of VT before the device implantation were independently associated with device intervention in patients with device implantation even after the adjustment of confounding factors (hazard ratio [HR], 2.90; 95% confidence interval [CI], 1.56-5.24; p=0.001 and HR, 4.34; 95% CI, 2.43-8.05; p<0.0001, respectively).
  
  
  CONCLUSIONS
  The presence of J wave and the documented history of VT prior to device implantation served as independent predictors of future device intervention for ventricular tachyarrhythmias.
authors.affiliation: Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan. Electronic address: hayashih@belle.shiga-med.ac.jp.
authors.forename: Hideki
authors.initials: H
authors.lastname: Hayashi
authors.affiliation: Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Horie
mesh_terms: D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D004562:Electrocardiography / Q000379:methods* / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D015995:Prevalence; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control*; D016896:Treatment Outcome
keywords: Cardiac resynchronization therapy-defibrillator; Electrocardiogram; Implantable cardioverter-defibrillator; J wave; Ventricular tachycardia