Embolic Risk Is Time-dependent

Abstract

The nice review by Klein und Trappe (1) should be supplemented by the data of Nuotio et al. (2). In a retrospective analysis of 5116 cardioversions without prior anticoagulation, thromboembolic events occurred only in 0.3% of patients when cardioversion was performed within the first 12 hours of atrial fibrillation. However, this rate increased to 1.1% when cardioversion was performed after more than 12 but less than 48 hours. The rate of thromboembolic events in the entire patient population was 0.7%, thus within the range of 0.3% to 0.8% reported elsewhere (3). In my view, the almost fourfold increase in risk of thromboembolic events observed when cardioversion is performed more than 12 hours after onset of atrial fibrillation indicates that it might be useful to review the practice of cardioversion without prior transesophageal echocardiography even after an atrial fibrillation duration of less than 48 hours and to initiate adequate oral anticoagulation therapy in all non-urgent cases with atrial fibrillation of more than 12 hours' duration.