title: Cardiac resynchronization therapy response is associated with shorter duration of atrial fibrillation.
abstract: BACKGROUND
  Atrial fibrillation (AF) is commonly associated with heart failure. The benefit of cardiac resynchronization therapy (CRT) on atrial remodeling has been demonstrated. However, biventricular pacing did not reduce the global incidence of AF. We evaluated the relationship between CRT response and AF duration.
  
  
  METHODS
  We retrospectively analyzed data from 96 patients (59 +/- 15 years; 78% male) who underwent CRT. All patients had class III-IV New York Heart Association (NYHA) symptoms despite maximal medical therapy, left ventricular ejection fraction (LVEF) < or = 35%, QRS >130 ms, and sinus rhythm before implantation. CRT response in patients who survived at six months of follow-up was defined as: (1) no hospitalization for heart failure and (2) improvement of one or more grades in the NYHA classification.
  
  
  RESULTS
  CRT responders (n = 54) and non-responders (n = 42) had similar baseline characteristics, including the incidence of persistent AF within six months before implantation. Six months after implantation, when compared to baseline, CRT responders exhibited a significant decrease in left atrial size (47.5 +/- 7.1 mm vs 44.6 +/- 7.7 mm, P < 0.01) and in the incidence of persistent AF (17% vs 2%, P = 0.02). At six months, CRT responders demonstrated shorter mean AF duration (7.5 +/- 43.3 hours vs 48.8 +/- 129.0 hours, P = 0.03) and lower incidence of persistent AF (2% vs 19%, P = 0.004) compared to nonresponders.
  
  
  CONCLUSIONS
  CRT response is associated with a reversal of atrial remodeling and a shorter AF duration.
authors.affiliation: UCLA Cardiac Arrhythmia Center, Division of Cardiology, Department of Medicine, David Geffen School of Medicine at UCLA, University of California-Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Lellouche
authors.forename: Carlos
authors.initials: C
authors.lastname: De Diego
authors.forename: Marmar
authors.initials: M
authors.lastname: Vaseghi
authors.forename: Eric
authors.initials: E
authors.lastname: Buch
authors.forename: David A
authors.initials: DA
authors.lastname: Cesario
authors.forename: Aman
authors.initials: A
authors.lastname: Mahajan
authors.forename: Isaac
authors.initials: I
authors.lastname: Wiener
authors.forename: Gregg C
authors.initials: GC
authors.lastname: Fonarow
authors.forename: Noel G
authors.initials: NG
authors.lastname: Boyle
authors.forename: Kalyanam
authors.initials: K
authors.lastname: Shivkumar
mesh_terms: D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000517:prevention & control*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome