title: Improvement of left atrial function is associated with lower incidence of atrial fibrillation and mortality after cardiac resynchronization therapy.
abstract: BACKGROUND
  Left atrial (LA) volume is a predictor of cardiovascular events in patients with heart failure. Improvement of LA function and reverse remodeling was observed after cardiac resynchronization therapy (CRT).
  
  
  OBJECTIVE
  The purpose of this study was to explore the clinical significance of improvement in LA function after CRT.
  
  
  METHODS
  Echocardiographic studies were performed before and 3 months after CRT in 97 patients (72 men and 25 women; age 63.8 +/- 13.3 years) with standard CRT indication but no history of atrial fibrillation (AF). LA active emptying fraction based on the change in volumes (LAV-EF) were calculated, and significant improvement in LA function (LA responder) was defined as a relative increase >/=50% from baseline LAV-EF. The primary end-points were newly developed AF detected by ECG or device and all-cause mortality.
  
  
  RESULTS
  After 1,200 +/- 705 days of follow-up, LA responders (n = 47 [48.5%]) had a significantly lower incidence of AF (12.8% vs 40%, P = .002) and mortality (17% vs 44%, P = .004) than did LA nonresponders. In Cox proportional hazard analysis, LA responders was the only independent predictor of lower risk of new-onset AF (hazard ratio 0.22, 95% confidence interval 0.08-0.61, P = .003), whereas both LA responders (hazard ratio 0.22, 95% confidence interval 0.09-0.53, P <.001) and left ventricular reverse remodeling (>10% reduction in left ventricular end-systolic volume at 3 months; hazard ratio 0.96, 95% confidence interval 0.93-0.99, P = .03) were independent predictors of lower risk of death after CRT.
  
  
  CONCLUSIONS
  Improvement of LA function after CRT was associated with a lower incidence of AF and mortality in AF naïve patients with severe heart failure.
authors.affiliation: Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China. jwhfung@cuhk.edu.hk
authors.forename: Jeffrey W H
authors.initials: JW
authors.lastname: Fung
authors.forename: Gabriel W K
authors.initials: GW
authors.lastname: Yip
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhang
authors.forename: Fang
authors.initials: F
authors.lastname: Fang
authors.forename: Joseph Y S
authors.initials: JY
authors.lastname: Chan
authors.forename: Chun Mei
authors.initials: CM
authors.lastname: Li
authors.forename: Li Wen
authors.initials: LW
authors.lastname: Wu
authors.forename: Gary C P
authors.initials: GC
authors.lastname: Chan
authors.forename: Hamish C K
authors.initials: HC
authors.lastname: Chan
authors.forename: Cheuk-Man
authors.initials: CM
authors.lastname: Yu
mesh_terms: D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000401:mortality / Q000517:prevention & control*; D002304:Cardiac Pacing, Artificial; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000294:innervation / Q000503:physiopathology*; D006333:Heart Failure / Q000628:therapy*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D014463:Ultrasonography; D020257:Ventricular Remodeling