title: Pacemaker-detected atrial fibrillation in patients with pacemakers: prevalence, predictors, and current use of oral anticoagulation.
abstract: BACKGROUND
  Dual-chamber pacemakers frequently document atrial fibrillation (AF) in patients without symptoms. Pacemaker-detected AF is associated with a 2.5-fold increased risk of stroke, although it is not established whether oral anticoagulation reduces this risk. This study sought to determine the prevalence and predictors of pacemaker-detected AF and to document current oral anticoagulant use.
  
  
  METHODS
  A retrospective analysis included all patients from a single academic hospital who had pacemakers capable of documenting AF. Blinded evaluation of all echocardiograms conducted within 6 months of implantation was performed.
  
  
  RESULTS
  Of 445 patients, pacemaker-detected AF was present in 246 (55.3%), who were older (74.3 ± 13.7 years vs 71.7 ± 14.4, P = 0.046), more likely to have a history of clinical AF (29.7% vs 19.1%, P = 0.01), and had a larger left atrial volume index (34.4 ± 11.8 mL/m(2) vs 30.0 ± 9.9 mL/m(2), P = 0.019) than the patients without pacemaker-detected AF. Among patients without a clinical history of AF, left atrial volume index was higher among those with pacemaker-detected AF (33.7 ± 11.3 mL/m(2) vs 29.0 ± 10.1 mL/m(2), P = 0.034). Anticoagulants were used in 35.3% of patients with pacemaker-detected AF, compared with 21.6% of patients without (P < 0.05). In patients with pacemaker-detected AF, anticoagulants were used more frequently among patients who also had clinical AF (58.9%) compared with those without (23.7%, P < 0.001).
  
  
  CONCLUSIONS
  Pacemaker-detected AF occurs in 50% of pacemaker patients and is treated with anticoagulants in less than 25% of patients who do not have a history of clinical AF. Clinical trials are needed to determine the role of anticoagulation in this population.
authors.affiliation: Population Health Research Institute, Hamilton, Ontario, Canada. Jeff.Healey@phri.ca
authors.forename: Jeff S
authors.initials: JS
authors.lastname: Healey
authors.forename: Jason L
authors.initials: JL
authors.lastname: Martin
authors.forename: Andrew
authors.initials: A
authors.lastname: Duncan
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Connolly
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Ha
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Morillo
authors.forename: Girish M
authors.initials: GM
authors.lastname: Nair
authors.forename: John
authors.initials: J
authors.lastname: Eikelboom
authors.forename: Syamkumar
authors.initials: S
authors.lastname: Divakaramenon
authors.forename: Hisham
authors.initials: H
authors.lastname: Dokainish
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage*; D001281:Atrial Fibrillation / Q000150:complications / Q000453:epidemiology / Q000628:therapy*; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009864:Ontario / Q000453:epidemiology; D010138:Pacemaker, Artificial; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D020521:Stroke / Q000209:etiology / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants