title: Cardiac resynchronization therapy is associated with reductions in left atrial volume and inappropriate implantable cardioverter-defibrillator therapy in MADIT-CRT.
abstract: BACKGROUND
  There are no prior studies assessing the relationship between left atrial volume (LAV) and inappropriate implantable cardioverter-defibrillator (ICD) therapy following treatment with cardiac resynchronization therapy.
  
  
  OBJECTIVE
  The purpose of this study was to investigate the hypothesis that patients randomized to cardiac resynchronization therapy with defibrillator (CRT-D) in the Multicenter Automatic Defibrillator Trial-Cardiac Resynchronization Therapy (MADIT-CRT) who had significant LAV reductions would have reduced risks of inappropriate ICD therapy.
  
  
  METHODS
  Cardiac resynchronization remodeling was assessed by measuring LAV change between baseline and 12-month echocardiograms in 751 CRT-D treated patients. Patients were stratified into quartiles based on percent reduction of LAV change. High LAV responders were those in the highest 3 quartiles of LAV reduction (LAV reduction ≥21%). Low LAV responders were those in the lowest quartile of LAV reduction (LAV reduction <21%). Clinical factors associated with ≥21% reduction in LAV were evaluated by linear regression analysis.
  
  
  RESULTS
  In Cox proportional hazards regression analyses, high LAV responders had a 39% reduction in the risk of inappropriate therapy (hazard ratio 0.61, P = .04) and left bundle branch block patients exhibited an even greater risk reduction in inappropriate therapy (hazard ratio 0.51, P = .02) compared to low LAV responders during follow-up extending up to 3 years after the 12-month echocardiogram. High LAV responders also had a significantly lower risk of heart failure or death during follow-up than did low LAV responders.
  
  
  CONCLUSIONS
  A ≥21% reduction in LAV with cardiac resynchronization therapy is associated with significant reductions in inappropriate ICD therapy and in heart failure or death during a 3-year follow-up.
authors: Heart Research Follow-up Program of the of the Department of Medicine, University of Rochester Medical Center, Rochester, New York.
authors: Tyler
authors: T
authors: Slyngstad
authors: Heart Research Follow-up Program of the of the Department of Medicine, University of Rochester Medical Center, Rochester, New York; Gentofte University Hospital, Department of Cardiology, Copenhagen, Denmark.
authors: Anne-Christine
authors: AC
authors: Huth Ruwald
authors: Heart Research Follow-up Program of the of the Department of Medicine, University of Rochester Medical Center, Rochester, New York.
authors: Valentina
authors: V
authors: Kutyifa
authors: Heart Research Follow-up Program of the of the Department of Medicine, University of Rochester Medical Center, Rochester, New York.
authors: Scott
authors: S
authors: McNitt
authors: Heart Research Follow-up Program of the of the Department of Medicine, University of Rochester Medical Center, Rochester, New York.
authors: Bronislava
authors: B
authors: Polonsky
authors: Brigham and Women's Hospital, Boston, Massachusetts.
authors: Scott D
authors: SD
authors: Solomon
authors: University of California San Francisco Hospital, San Francisco, California.
authors: Elyse
authors: E
authors: Foster
authors: Sheba Medical Center and Tel Aviv University, Tel Aviv, Israel.
authors: Ilan
authors: I
authors: Goldenberg
authors: Cardiology Division, Stanford University School of Medicine, Palo Alto, California.
authors: Paul J
authors: PJ
authors: Wang
authors: Heart Research Follow-up Program of the of the Department of Medicine, University of Rochester Medical Center, Rochester, New York.
authors: Helmut
authors: H
authors: Klein
authors: Heart Research Follow-up Program of the of the Department of Medicine, University of Rochester Medical Center, Rochester, New York.
authors: Wojciech
authors: W
authors: Zareba
authors: Heart Research Follow-up Program of the of the Department of Medicine, University of Rochester Medical Center, Rochester, New York. Electronic address: heartajm@heart.rochester.edu.
authors: Arthur J
authors: AJ
authors: Moss
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000473:pathology / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000379:methods; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data; D005260:Female; D006325:Heart Atria / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D017180:Tachycardia, Ventricular / Q000209:etiology
keywords: Cardiac resynchronization therapy; Echocardiography; Inappropriate implantable cardioverter-defibrillator therapy; Left atrial volume