title: Effect of cardiac resynchronization therapy on the risk of first and recurrent ventricular tachyarrhythmic events in MADIT-CRT.
abstract: OBJECTIVE
  This study aimed to evaluate the effect of cardiac resynchronization therapy with a defibrillator (CRT-D) on the risks of first and recurrent ventricular tachyarrhythmic events (VTEs) in the MADIT-CRT.
  
  
  BACKGROUND
  Reverse remodeling associated with CRT-D therapy was suggested to reduce arrhythmic risk. However, the effect of the device on the risk of recurrent VTEs among patients who experience a first arrhythmic event has not been investigated.
  
  
  METHODS
  The CRT-D versus defibrillator-only risks for first and subsequent fast VTEs (>180 beats/min) were assessed by Cox proportional hazards and Andersen-Gill proportional intensity regression modeling, respectively, in efficacy analyses recognizing active device-type during follow-up.
  
  
  RESULTS
  Multivariate analysis showed that CRT-D was associated with a significant 29% (p = 0.003) reduction in the risk of a first VTE, with a pronounced effect among patients with left bundle branch block (LBBB) (hazard ratio [HR]: 0.58; p < 0.001) and no significant effect among non-LBBB patients (HR: 1.05; p = 0.82, p for the difference = 0.02). Patients with LBBB who experienced a first VTE had no change in the risk of subsequent VTEs with CRT-D (HR: 0.98; p = 0.85). In contrast, the risk of recurrent VTEs with CRT-D was significantly increased among non-LBBB patients (HR: 3.62; p = 0.002, p for the difference = 0.009). Recurrent VTEs increased the risk of subsequent heart failure or death.
  
  
  CONCLUSIONS
  In MADIT-CRT, active treatment with CRT-D was associated with a significant reduction in the risk of life-threatening VTEs. However, our findings suggest that CRT-D does not reduce the risk of subsequent VTEs in patients who experience a first arrhythmic event and may increase subsequent arrhythmic risk in non-LBBB patients. (Multicenter Automatic Defibrillator Implantation With Cardiac Resynchronization Therapy [MADIT-CRT]; NCT00180271).
authors.affiliation: Cardiology Division, Department of Medicine, University of Rochester, Rochester, New York 14642, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Ouellet
authors.forename: David T
authors.initials: DT
authors.lastname: Huang
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Moss
authors.forename: W Jackson
authors.initials: WJ
authors.lastname: Hall
authors.forename: Alon
authors.initials: A
authors.lastname: Barsheshet
authors.forename: Scott
authors.initials: S
authors.lastname: McNitt
authors.forename: Helmut
authors.initials: H
authors.lastname: Klein
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zareba
authors.forename: Ilan
authors.initials: I
authors.lastname: Goldenberg
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006333:Heart Failure; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D012008:Recurrence; D012044:Regression Analysis; D012306:Risk; D017180:Tachycardia, Ventricular / Q000209:etiology / Q000503:physiopathology*; D016896:Treatment Outcome