Background Electrical cardioversion (ECV) is routinely used to restore sinus rhythm in patients with symptomatic atrial fibrillation. The European guidelines have been updated in recent years. Current information on differences in the risk for stroke after acute versus elective ECV is lacking. Methods And Results All patients with a first-time acute or elective ECV in the Stockholm regional health care data warehouse from 2011 to 2018 were included. Cox regression analyses were performed evaluating ischemic or unspecified stroke within 30 days after ECV with adjustments for the CHA2DS2-VASc score, medical treatment, and year of inclusion. The study included 9139 patients, 3094 after acute and 6045 after elective ECV. The mean age was 65.9±11.3 years, 69.5% were men, and the mean CHA2DS2-VASc score was 2.4±1.7. Before the intervention, 49.6% of patients with an acute ECV and 96.4% of those with an elective ECV had claimed an oral anticoagulant prescription. Ischemic or unspecified stroke occurred in 26 (0.28%) patients within 30 days. The unadjusted risk was higher after acute compared with elective ECV (hazard ratio [HR], 2.29; 95% CI, 1.06-4.96), whereas there was no difference after multivariable adjustments (adjusted HR, 0.99; 95% CI, 0.36-2.72). Both non-vitamin K oral anticoagulants (adjusted HR, 0.28; 95% CI, 0.08-0.98) and warfarin (adjusted HR, 0.17; 95% CI, 0.05-0.53) were associated with a lower risk for stroke compared with no anticoagulation. Conclusions Acute ECV was associated with a higher unadjusted risk for stroke than elective ECV, but the risk was similar after adjustment for anticoagulant treatment. This study indicates the importance of anticoagulation before ECV according to recent European guidelines.
Keywords: anticoagulant; arrhythmia; atrial fibrillation; cardioversion; thromboembolism.