title: Newly detected atrial fibrillation following dual chamber pacemaker implantation.
abstract: BACKGROUND
  Pacemaker (PPM)-detected atrial high-rate episodes (AHREs) of even 5-minute duration may identify patients at increased risk for stroke and death. In this study, we sought to determine the incidence of newly detected atrial fibrillation (AF defined as an AHRE > or = 5 minutes) in patients following dual-chamber PPM implantation and to define the clinical predictors of developing AF.
  
  
  RESULTS
  We evaluated 262 patients (142 male; age 74 +/- 12 years) without documented AF who underwent PPM implantation for sinus node dysfunction (n = 122) or atrioventricular block (n = 140). Information regarding patient demographics, cardiovascular diseases, and medication history was obtained. The cumulative percentages of ventricular pacing as well as the frequency, duration, and time to first episode of an AHRE were also determined. During follow-up of 596 +/- 344 days, an AHRE > or = 5 minutes was detected in 77 (29%) patients. Of these, 47 (61%) patients had an AHRE > or = 1 hour, 22 (29%) patients had an AHRE > or = 1 day, and 12 (16%) patients had an AHRE > or = 1 week. An AHRE > or = 5 minutes was seen in 24% and 34% of patients at 1 year and 2 years, respectively. Among patients with sinus node dysfunction, > or = 50% cumulative ventricular pacing was the only significant predictor of an AHRE > or = 5 minutes (HR 2.2; CI 1.0-4.7; P = 0.04).
  
  
  CONCLUSIONS
  Within 1 year of PPM implantation, AF is detected in 24% of patients without history of AF. In patients with sinus node dysfunction, > or = 50% cumulative right ventricular pacing is associated with a 2-fold increase in risk of developing AF.
authors.affiliation: Division of Cardiology, Department of Medicine, Cornell University Medical Center, New York, New York 10021, USA.
authors.forename: Jim W
authors.initials: JW
authors.lastname: Cheung
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Keating
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Stein
authors.forename: Steven M
authors.initials: SM
authors.lastname: Markowitz
authors.forename: Sei
authors.initials: S
authors.lastname: Iwai
authors.forename: Bindi K
authors.initials: BK
authors.lastname: Shah
authors.forename: Bruce B
authors.initials: BB
authors.lastname: Lerman
authors.forename: Suneet
authors.initials: S
authors.lastname: Mittal
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000453:epidemiology*; D002304:Cardiac Pacing, Artificial / Q000706:statistics & numerical data*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009518:New York / Q000453:epidemiology; D010138:Pacemaker, Artificial / Q000706:statistics & numerical data*; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors