title: The effect of intermittent atrial tachyarrhythmia on heart failure or death in cardiac resynchronization therapy with defibrillator versus implantable cardioverter-defibrillator patients: a MADIT-CRT substudy (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy).
abstract: OBJECTIVE
  This study aimed to investigate the effect of both history of intermittent atrial tachyarrhythmias (IAT) and in-trial IAT on the risk of heart failure (HF) or death comparing cardiac resynchronization therapy with defibrillator (CRT-D) to implantable cardioverter-defibrillator (ICD) treatment in mildly symptomatic HF patients with left bundle branch block (LBBB).
  
  
  BACKGROUND
  Limited data exist regarding the benefit of CRT-D in patients with IAT.
  
  
  METHODS
  The benefit of CRT-D in reducing the risk of HF/death was evaluated using multivariate Cox models incorporating the presence of, respectively, a history of IAT at baseline and time-dependent development of in-trial IAT during follow-up in 1,264 patients with LBBB enrolled in the MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy) study.
  
  
  RESULTS
  The overall beneficial effect of CRT-D versus ICD on the risk of HF/death was not significantly different between LBBB patients with or without history of IAT (HR: 0.50, p = 0.028, and HR: 0.46, p < 0.001, respectively; p for interaction = 0.79). Among patients who had in-trial IAT, CRT-D was associated with a significant 57% reduction in the risk of HF/death compared with ICD-only therapy (HR: 0.43, p = 0.047), similar to the effect of the device among patients who did not have IAT (HR: 0.47, p < 0.001; p for interaction = 0.85). The percentage of patients with biventricular pacing ≥92% was similar in both groups (p = 0.43). Consistent results were shown for the benefit of CRT-D among patients who had in-trial atrial fibrillation/flutter (HR: 0.30, p = 0.027; p for interaction = 0.41).
  
  
  CONCLUSIONS
  In the MADIT-CRT study, the clinical benefit of CRT-D in LBBB patients was not attenuated by prior history of IAT or by the development of in-trial atrial tachyarrhythmias. (MADIT-CRT: Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy; NCT00180271).
authors: University of Rochester Medical Center, Heart Research Follow-Up Program, Rochester, New York; Department of Cardiology, Gentofte University Hospital, Hellerup, Denmark. Electronic address: anne.ruwald@heart.rochester.edu.
authors: Anne-Christine
authors: AC
authors: Ruwald
authors: Division of Cardiology, University of Buffalo, Buffalo, New York.
authors: Grzegorz
authors: G
authors: Pietrasik
authors: University of Rochester Medical Center, Heart Research Follow-Up Program, Rochester, New York; Heart Institute, Sheba Medical Center, Tel Hashomer, Israel.
authors: Ilan
authors: I
authors: Goldenberg
authors: University of Rochester Medical Center, Heart Research Follow-Up Program, Rochester, New York; Semmelweis University Heart Center, Budapest, Hungary.
authors: Valentina
authors: V
authors: Kutyifa
authors: Cardiology Division, Duke University Medical Center, Durham, North Carolina.
authors: James P
authors: JP
authors: Daubert
authors: University of Rochester Medical Center, Heart Research Follow-Up Program, Rochester, New York; Department of Cardiology, Gentofte University Hospital, Hellerup, Denmark.
authors: Martin H
authors: MH
authors: Ruwald
authors: Department of Cardiology, Gentofte University Hospital, Hellerup, Denmark.
authors: Christian
authors: C
authors: Jons
authors: University of Rochester Medical Center, Heart Research Follow-Up Program, Rochester, New York.
authors: Scott
authors: S
authors: McNitt
authors: Division of Cardiovascular Medicine, Stanford University, Stanford, California.
authors: Paul
authors: P
authors: Wang
authors: University of Rochester Medical Center, Heart Research Follow-Up Program, Rochester, New York.
authors: Wojciech
authors: W
authors: Zareba
authors: University of Rochester Medical Center, Heart Research Follow-Up Program, Rochester, New York.
authors: Arthur J
authors: AJ
authors: Moss
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy; D009202:Cardiomyopathies / Q000401:mortality / Q000628:therapy*; D047548:Defibrillators; D017147:Defibrillators, Implantable; D004554:Electric Countershock; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging; D006333:Heart Failure / Q000453:epidemiology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D013610:Tachycardia / Q000453:epidemiology*; D014463:Ultrasonography
keywords: atrial arrhythmia; cardiac resynchronization therapy; death; efficacy; heart failure; implantable cardioverter-defibrillator; left atrial volume; left bundle branch block; reverse remodeling