Risk factors for thromboembolism in patients with paroxysmal atrial fibrillation

There is some controversy concerning which clinical characteristics predict thromboembolism and whether treatment with class I antiarrhythmic drugs re duces thromboembolim in patients with paroxysmal atrial fibrillation (AF), This retrospective, multicenter study was undertaken to determine risk fact or or factors for thromboembolism in patients with paroxysmal AF. Seven hun dred forty patients with paroxysmal AF (mean age 56 years) without prior th romboembolic events were followed retrospectively. Cerebral thromboembolism , including transient ischemic attack and embolism of peripheral arteries, were selected as primary end points, Independent risk factors were determin ed with multivariate analysis, and event-free survival curves were estimate d. During 3.4-year follow-up period, primary end points occurred in 55 pati ents (2.2% per year). Patients with thromboembolism had a higher prevalence of underlying heart disease (p <0.01), less frequent treatment with antiar rhythmic drugs (p <0.01), and received diuretics more often (p <0.01) compa red with patients without thromboembolism, Age (greater than or equal to 65 years, RR 3.33, p = 0.0001) and gender (male, RR = 2, p = 0.0291) emerged as predictors of thromboembolism by multivariate analysis with Cox's propor tional hazard model. Treatment with antiarrhythmic drugs (RR = 0.57, p = 0. 0578) and aspirin (RR = 0.52, p = 0.1094) showed trends coward reducing thr omboembolic risks. It is suggested that elderly men (greater than or equal to 65 years) with paroxysmal AF are at risk for thromboembolism, but the ri sk tended to be reduced by treatment with antiarrhythmic drugs and aspirin. (C) 2000 by Excerpta Medica, Inc.