title: Bidirectional association between atrial fibrillation and congestive heart failure in the elderly.
abstract: OBJECTIVE
  The aim of this study was to examine the bidirectional association between atrial fibrillation and congestive heart failure (CHF) in older adults.
  
  
  METHODS
  We studied the association of atrial fibrillation at entry with incident CHF (N = 5281; 85% white, 42% male) and the association of CHF at entry with incident atrial fibrillation (N = 5233; 85% white, 42% male) in the Cardiovascular Health Study (CHS). Baseline atrial fibrillation was identified during the study electrocardiogram and by self-reported history, and incident cases were identified during subsequent study electrocardiograms and hospitalization data. Baseline CHF was identified by self-reported history and adjudication of medical records, and incident cases were identified using hospitalization data. Cox regression was used to compute hazard ratios and 95% confidence intervals (CIs) for the association between atrial fibrillation and incident CHF, and CHF and incident atrial fibrillation, separately.
  
  
  RESULTS
  Over a median follow-up of 12.6 years, 534 (10%) participants developed atrial fibrillation. CHF was associated with an increased risk of atrial fibrillation (hazard ratio 2.0, 95% CI 1.4, 3.0). A total of 1692 (32%) participants developed CHF over a median follow-up of 11.7 years and atrial fibrillation was associated with an increased risk of CHF (hazard ratio 1.9, 95% CI 1.5, 2.2).
  
  
  CONCLUSIONS
  Our results suggest that a bidirectional relationship exists between atrial fibrillation and CHF, with each condition influencing the development of the other.
authors.affiliation: aDepartment of Internal Medicine bDepartment of Internal Medicine, Section on Cardiology cEpidemiological Cardiology Research Center (EPICARE), Department of Epidemiology and Prevention, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
authors.forename: Wesley T
authors.initials: WT
authors.lastname: O'Neal
authors.forename: Waqas
authors.initials: W
authors.lastname: Qureshi
authors.forename: Zhu-Ming
authors.initials: ZM
authors.lastname: Zhang
authors.forename: Elsayed Z
authors.initials: EZ
authors.lastname: Soliman
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000150:complications* / Q000453:epidemiology; D005260:Female; D006333:Heart Failure / Q000150:complications* / Q000453:epidemiology; D006801:Humans; D008297:Male; D011446:Prospective Studies; D014481:United States / Q000453:epidemiology