title: Progression to chronic atrial fibrillation after pacing: the Canadian Trial of Physiologic Pacing. CTOPP Investigators.
abstract: OBJECTIVE
  This study examined the effect of physiologic pacing on the development of chronic atrial fibrillation (CAF) in the Canadian Trial Of Physiologic Pacing (CTOPP).
  
  
  BACKGROUND
  The role of physiologic pacing to prevent CAF remains unclear. Small randomized studies have suggested a benefit for patients with sick sinus syndrome. No data from a large randomized trial are available.
  
  
  METHODS
  The CTOPP randomized patients undergoing first pacemaker implant to ventricular-based or physiologic pacing (AAI or DDD). Patients who were prospectively found to have persistent atrial fibrillation (AF) lasting greater than or equal to one week were defined as having CAF. Kaplan-Meier plots for the development of CAF were compared by log-rank test. The effect of baseline variables on the benefit of physiologic pacing was evaluated by Cox proportional hazards modeling.
  
  
  RESULTS
  Physiologic pacing reduced the development of CAF by 27.1%, from 3.84% per year to 2.8% per year (p = 0.016). Three clinical factors predicted the development of CAF: age > or =74 years (p = 0.057), sinoatrial (SA) node disease (p < 0.001) and prior AF (p < 0.001). Subgroup analysis demonstrated a trend for patients with no history of myocardial infarction or coronary disease (p = 0.09) as well as apparently normal left ventricular function (p = 0.11) to derive greatest benefit.
  
  
  CONCLUSIONS
  Physiologic pacing reduces the annual rate of development of chronic AF in patients undergoing first pacemaker implant. Age > or =74 years, SA node disease and prior AF predicted the development of CAF. Patients with structurally normal hearts appear to derive greatest benefits.
authors.affiliation: Division of Cardiology, University of Western Ontario, London, Canada. allan.skanes@lhsc.on.ca
authors.forename: A C
authors.initials: AC
authors.lastname: Skanes
authors.forename: A D
authors.initials: AD
authors.lastname: Krahn
authors.forename: R
authors.initials: R
authors.lastname: Yee
authors.forename: G J
authors.initials: GJ
authors.lastname: Klein
authors.forename: S J
authors.initials: SJ
authors.lastname: Connolly
authors.forename: C R
authors.initials: CR
authors.lastname: Kerr
authors.forename: M
authors.initials: M
authors.lastname: Gent
authors.forename: K E
authors.initials: KE
authors.lastname: Thorpe
authors.forename: R S
authors.initials: RS
authors.lastname: Roberts
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000517:prevention & control*; D002170:Canada; D002304:Cardiac Pacing, Artificial; D002908:Chronic Disease; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D016278:Ventricular Function, Right