Stroke Risk With Cardioversion for Atrial Fibrillation
What is the risk of thromboembolism after cardioversion within 48 hours of atrial fibrillation (AF) onset in patients therapeutically versus not therapeutically anticoagulated?
Using a single-center database, patients undergoing electrical cardioversion within 48 hours of AF onset were identified. They were split into two cohorts, based on the presence or absence of anticoagulation therapy within 30 days post-cardioversion. Rates of major thromboembolic events at 30 days were calculated.
Among 567 cardioversions in 484 patients without any therapeutic anticoagulation, six (1.06%) experienced neurological events. All of these affected patients were treated with aspirin monotherapy. Among 898 cardioversions in 709 patients on therapeutic anticoagulation, two (0.22%) experienced neurological events. Patients forgoing anticoagulation therapy had higher odds of neurological events (odds ratio, 4.8; p = 0.03). No thromboembolic events occurred in patients with a CHA2DS2-VASc score <2 or in patients with postoperative AF.
The authors concluded that patients with acute-onset AF are at a higher risk of thromboembolic events when anticoagulation therapy is withheld. The authors also note that postoperative AF patients and AF patients at low risk of stroke may not require anticoagulant therapy.
Management of AF patients undergoing cardioversion involves two major clinical dilemmas: 1) the need for pre-cardioversion anticoagulation or transesophageal echocardiogram, and 2) the need for anticoagulation following cardioversion. This study suggests that post-cardioversion anticoagulation may be beneficial for patients at moderate to high risk of stroke (CHA2DS2-VASc score ≥2) whose AF did not occur in a postoperative setting. The next question remaining to be answered is how long to continue anticoagulation therapy if the cardioversion is deemed a success.
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