Incidence of Thromboembolic Complications Within 30 Days of Electrical Cardioversion Performed Within 48 Hours of Atrial Fibrillation Onset

This study sought to compare the risk of thromboembolism after cardioversion within 48 h of atrial fibrillation (AF) onset in patients therapeutically versus not therapeutically anticoagulated.

Although guidelines do not mandate anticoagulation for cardioversion within 48 h of AF onset, risk of thromboembolism in this group has been understudied.

Patients undergoing cardioversion within 48 h after AF onset were identified from a prospectively collected database and retrospectively reviewed to determine anticoagulation status and major thromboembolic events within 30 days of cardioversion.

Among 567 cardioversions in 484 patients without therapeutic anticoagulation (mean CHA₂DS₂-VASc score, 2.3 ± 1.7), 6 had neurological events (1.06%), all in patients on aspirin alone. Among 898 cardioversions in 709 patients on therapeutic anticoagulation (mean CHA₂DS₂-VASc score, 2.6 ± 1.7; p = 0.017), 2 neurological events occurred (0.22%; OR: 4.8; p = 0.03), both off anticoagulation at the time of stroke. No thromboembolic events occurred in patients with CHA₂DS₂-VASc score <2 (p = 0.06) or in patients with postoperative AF.

In patients with acute-onset AF, odds of thromboembolic complications were almost 5 times higher in patients without therapeutic anticoagulation at the time of cardioversion. However, no events occurred in post-operative patients and in those with CHA₂DS₂-VASc scores of <2, supporting the utility of accurate assessment of AF onset and risk stratification in determining the need for anticoagulation for cardioversion of AF <48 h in duration.