title: Cardiac resynchronization therapy reduces left atrial volume and the risk of atrial tachyarrhythmias in MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy).
abstract: OBJECTIVE
  We hypothesized that reductions in left atrial volume (LAV) with a cardiac resynchronization therapy-defibrillator (CRT-D) would translate into a subsequent reduction in the risk of atrial tachyarrhythmias (AT).
  
  
  BACKGROUND
  There is limited information regarding the effect of CRT-D on the risk of AT.
  
  
  METHODS
  Percent reduction in LAV at 1 year following CRT-D implantation (pre-specified as low [lowest quartile: <20% reduction in LAV] and high [≥20% reduction in LAV] response to CRT-D) were related to the risk of subsequent AT (comprising atrial fibrillation, atrial flutter, atrial tachycardia, and supraventricular tachyarrhythmias) among patients enrolled in MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy).
  
  
  RESULTS
  The cumulative probability of AT 2.5 years after assessment of echocardiographic response was lowest among high LAV responders to CRT-D (3%) and significantly higher among both low LAV responders to CRT-D (9%) and implantable cardioverter-defibrillator-only patients (7%; p = 0.03 for the difference among the 3 groups). Consistently, multivariate analysis showed that high LAV responders to CRT-D experienced a significant 53% (p = 0.01) reduction in the risk of subsequent AT as compared with implantable cardioverter-defibrillator-only patients, whereas low LAV responders did not derive a significant risk reduction with CRT-D therapy (hazard ratio [HR]: 1.05 [95% confidence interval (CI): 0.54 to 2.00]; p = 0.89). Patients who developed in-trial AT experienced significant increases in the risk for both the combined endpoint of heart failure or death (HR: 2.28 [95% CI: 1.45 to 3.59]; p < 0.001) and the separate occurrence of all-cause mortality (HR: 1.89 [95% CI: 1.08 to 3.62]; p = 0.01).
  
  
  CONCLUSIONS
  In the MADIT-CRT study, favorable reverse remodeling of the left atrium with CRT-D therapy was associated with a significant reduction in risk of subsequent AT. (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy [MADIT-CRT]; NCT00180271).
authors: Cardiology Division, Department of Medicine, University of Rochester Medical Center, Rochester, NY, USA.
authors: Andrew
authors: A
authors: Brenyo
authors: Mark S
authors: MS
authors: Link
authors: Alon
authors: A
authors: Barsheshet
authors: Arthur J
authors: AJ
authors: Moss
authors: Wojciech
authors: W
authors: Zareba
authors: Paul J
authors: PJ
authors: Wang
authors: Scott
authors: S
authors: McNitt
authors: David
authors: D
authors: Huang
authors: Elyse
authors: E
authors: Foster
authors: Mark
authors: M
authors: Estes
authors: Scott D
authors: SD
authors: Solomon
authors: Ilan
authors: I
authors: Goldenberg
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D017147:Defibrillators, Implantable; D004452:Echocardiography / Q000379:methods; D005260:Female; D006325:Heart Atria / Q000473:pathology; D006333:Heart Failure / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D012306:Risk; D013610:Tachycardia / Q000628:therapy*