Thromboembolism after atrioventricular node ablation and pacing: long termfollow up

Objective-To assess the incidence of arterial embolic events in patients wi th high rate, drug resistant, severely symptomatic paroxysmal and chronic a trial fibrillation who have undergone atrioventricular (AV) node ablation a nd permanent pacing. Design-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) year s) with high rate, drug resistant paroxysmal atrial fibrillation (308) or c hronic atrial fibrillation (277). Lone atrial fibrillation was present in 1 33 patients, while the remaining 452 suffered from dilated, ischaemic, or v alvar 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 wer e observed in 17 patients (3%); the actuarial occurrence rates of thromboem bolism were 1.1%, 3%, 4.2%, and 7.4% after one, three, five, and seven year s, respectively. Among five variables, univariate analysis showed that only the presence of chronic atrial fibrillation at the time of ablation (relat ive 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 = 0.0 48) were associated with a significantly higher risk of occurrence of throm boembolic events. On multivariate analysis the only predictor of embolic ev ents during the follow up was the presence of chronic atrial fibrillation. Conclusions-Data from this large cohort of patients indicate a fairly low i ncidence (1.04% per year) of thromboembolic events after AV node ablation a nd pacing for drug refractory, high rate atrial fibrillation.