Thromboembolic Complications After Cardioversion of Acute Atrial Fibrillation: The FinCV Study

Study Questions:

What is the risk of stroke associated with transthoracic cardioversion of atrial fibrillation (AF) in the absence of anticoagulation?


In this retrospective database analysis at three hospitals, 2,481 patients (mean age 61 years) with AF for <48 hours who underwent cardioversion without anticoagulation were identified. The primary outcome was thromboembolic events within 30 days of cardioversion.


The 2,481 patients underwent 5,362 cardioversions, with a 95.4% success rate. The incidence of thromboembolic events in the 30 days post-cardioversion (median 2 days) was 0.7%, including a 0.6% incidence of stroke. The only independent predictors of thromboembolic events were age (odds ratio [OR], 1.05), female gender (OR, 2.1), heart failure (OR, 2.9), and diabetes (OR, 2.3). Patients with heart failure and diabetes had the highest risk of thromboembolism (9.8%). Patients ages <60 years without heart failure had the lowest risk of thromboembolism (0.2%).


The risk of thromboembolic complications in the absence of anticoagulation after cardioversion of AF <48 hours in duration is very low in the absence of risk factors for stroke, but unacceptably high in patients with risk factors.


Current guidelines for anticoagulation in patients undergoing cardioversion of AF are based on the duration of AF. Anticoagulation is recommended if the AF duration is >48 hours or unknown. If the AF duration is <48 hours, anticoagulation is recommended in patients with risk factors for stroke. Although the recommendations dealing with short-lived AF are very reasonable, there has been little evidence underlying the recommendations. This study is important because it provides substantial evidence that validates current practice guidelines.

Keywords: Thromboembolism, Incidence, Blood Coagulation, Stroke, Warfarin, Electric Countershock, Heart Failure, Risk Factors, Diabetes Mellitus

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