Prevalence and clinical characteristics of patients with atrial fibrillation - Analysis of 20,000 cases in Japan

In Japan, data on the epidemiological and clinical features of atrial fibri llation (AF) are rather sparse; even less data are available on the risk of thromboembolism in nonvalvular AF. The present study enrolled 19,825 patie nts who visited the cardiovascular clinics of the 13 hospitals in Hokkaido, Japan, between March and July 1995. The prevalence of AF, the clinical cha racteristics of AF patients, and the occurrence of ischemic events were exa mined during the 2 year follow-up period. The prevalence of AF increased wi th age, and the overall prevalence was 14%. Antithrombotic therapy was used in 57% of AF patients and the incidence of ischemic events during the foll ow-up period was 4.6% in all AF patients. Warfarin reduced the risk of isch emic events in both the valvular and nonvalvular AF groups. A history of ce rebrovascular accidents, advanced age, and the presence of underlying heart disease were each associated with a significantly increased risk of ischem ic events in the nonvalvular AF group. These results show a lower incidence of ischemic events and more frequent use of antiplatelet drugs in the nonv alvular AF group. Further prospective studies are needed to determine the b est preventive methods for thromboembolic complications in Japanese patient s with nonvalvular AF.