title: Thromboembolism after atrioventricular node ablation and pacing: long term follow up.
abstract: OBJECTIVE
  To assess the incidence of arterial embolic events in patients with high rate, drug resistant, severely symptomatic paroxysmal and chronic atrial fibrillation who have undergone atrioventricular (AV) node ablation and permanent pacing.
  
  
  METHODS
  Multicentre retrospective cohort study. PATIENTS AND MANAGEMENT: From May 1987 to January 1997, AV node ablation was performed in 585 severely symptomatic patients (mean (SD) age 66 (11) years) with high rate, drug resistant paroxysmal atrial fibrillation (308) or chronic atrial fibrillation (277). Lone atrial fibrillation was present in 133 patients, while the remaining 452 suffered from dilated, ischaemic, or valvar heart disease. Patients underwent VVIR (454) or DDDR (131) pacemaker implantation, after AV node ablation. Antiplatelet agents were given to 202 patients, warfarin to 187 patients.
  
  
  RESULTS
  During a follow up of 33.6 (24.2) months, thromboembolic events were observed in 17 patients (3%); the actuarial occurrence rates of thromboembolism were 1.1%, 3%, 4.2%, and 7.4% after one, three, five, and seven years, respectively. Among five variables, univariate analysis showed that only the presence of chronic atrial fibrillation at the time of ablation (relative risk (RR) = 1.8, 95% confidence interval (CI) = 1.02 to 3. 20, p = 0.04) and the need for warfarin treatment (RR = 1.6, 95% CI 1.00 to 2.71, p = 0.048) were associated with a significantly higher risk of occurrence of thromboembolic events. On multivariate analysis the only predictor of embolic events during the follow up was the presence of chronic atrial fibrillation.
  
  
  CONCLUSIONS
  Data from this large cohort of patients indicate a fairly low incidence (1.04% per year) of thromboembolic events after AV node ablation and pacing for drug refractory, high rate atrial fibrillation.
authors.affiliation: Department of Cardiology, Istituto Clinico Humanitas, 56 Rozzano, 20089 Milan, Italy. maurizio.gasparini@humanitas.it
authors.forename: M
authors.initials: M
authors.lastname: Gasparini
authors.forename: M
authors.initials: M
authors.lastname: Mantica
authors.forename: M
authors.initials: M
authors.lastname: Brignole
authors.forename: L
authors.initials: L
authors.lastname: Gianfranchi
authors.forename: C
authors.initials: C
authors.lastname: Menozzi
authors.forename: F
authors.initials: F
authors.lastname: Pizzetti
authors.forename: G
authors.initials: G
authors.lastname: Magenta
authors.forename: P
authors.initials: P
authors.lastname: Delise
authors.forename: A
authors.initials: A
authors.lastname: Proclemer
authors.forename: S
authors.initials: S
authors.lastname: Tognarin
authors.forename: R
authors.initials: R
authors.lastname: Ometto
authors.forename: F
authors.initials: F
authors.lastname: Acquati
authors.forename: R
authors.initials: R
authors.lastname: Mantovan
authors.forename: P
authors.initials: P
authors.lastname: Turco
authors.forename: G M
authors.initials: GM
authors.lastname: De Ferrari
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000150:complications / Q000601:surgery*; D001283:Atrioventricular Node; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation; D002908:Chronic Disease; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D011183:Postoperative Complications; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012306:Risk; D013923:Thromboembolism / Q000209:etiology*; D014859:Warfarin / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D010975:Platelet Aggregation Inhibitors; D014859:Warfarin