title: Chronic atrial fibrillation and stroke in paced patients with sick sinus syndrome. Relevance of clinical characteristics and pacing modalities.
abstract: BACKGROUND
  The goal of the report was to study the long-term incidence and the independent predictors for chronic atrial fibrillation and stroke in 507 paced patients with sick sinus syndrome, adjusting for differences in baseline clinical variables with multivariate analysis.
  
  
  RESULTS
  From 1980 to 1989, we implanted 376 dual-chamber, 19 atrial, and 112 ventricular pacemakers to treat patients with sick sinus syndrome. After a maximum follow-up of 134 months (mean: 59 +/- 38 months for chronic atrial fibrillation, 65 +/- 37 months for stroke), actuarial incidence of chronic atrial fibrillation was 7% at 1 year, 16% at 5 years, and 28% at 10 years. Independent predictors for this event, from Cox's proportional hazards model, were history of paroxysmal atrial fibrillation (P < .001; hazard ratio [HR] = 16.84), use of antiarrhythmic drugs before pacemaker implant (P < .001; HR = 2.25), ventricular pacing mode (P = .003; HR = 1.98), age (P = .005; HR = 1.03), and valvular heart disease (P = .008; HR = 2.05). For patients with preimplant history of paroxysmal atrial fibrillation, independent predictors were prolonged episodes of paroxysmal atrial fibrillation (P < .001; HR = 2.56), long history of paroxysmal atrial fibrillation (P = .004; HR = 2.05), ventricular pacing mode (P = .025; HR = 1.69), use of antiarrhythmic drugs before pacemaker implant (P = .024; HR = 1.71), and age (P = .04; HR = 1.02). Actuarial incidence of stroke was 3% at 1 year, 5% at 5 years, and 13% at 10 years. Independent predictors for stroke were history of cerebrovascular disease (P < .001; HR = 5.22), ventricular pacing mode (P = .008; HR = 2.61), and history of paroxysmal atrial fibrillation (P = .037; HR = 2.81).
  
  
  CONCLUSIONS
  Development of chronic atrial fibrillation and stroke in paced patients with sick sinus syndrome are strongly determined by clinical variables and secondarily by the pacing modality. Ventricular pacing mode predicts chronic atrial fibrillation in patients with preimplant paroxysmal atrial fibrillation but not in those without it.
authors.affiliation: Department of Cardiology, Cleveland Clinic Foundation, OH 44195.
authors.forename: E B
authors.initials: EB
authors.lastname: Sgarbossa
authors.forename: S L
authors.initials: SL
authors.lastname: Pinski
authors.forename: J D
authors.initials: JD
authors.lastname: Maloney
authors.forename: T W
authors.initials: TW
authors.lastname: Simmons
authors.forename: B L
authors.initials: BL
authors.lastname: Wilkoff
authors.forename: L W
authors.initials: LW
authors.lastname: Castle
authors.forename: R G
authors.initials: RG
authors.lastname: Trohman
mesh_terms: D000206:Actuarial Analysis; D000368:Aged; D001281:Atrial Fibrillation / Q000453:epidemiology*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D002561:Cerebrovascular Disorders / Q000453:epidemiology*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009017:Morbidity; D015999:Multivariate Analysis; D010138:Pacemaker, Artificial; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D012804:Sick Sinus Syndrome / Q000453:epidemiology / Q000628:therapy*; D013997:Time Factors