Catheter ablation has become a common treatment for atrial fibrillation (AF), and many patients undergo the procedure in hopes of stopping anticoagulation. However, the risks and benefits of discontinuing anticoagulation after successful ablation have not been clearly defined. Current guidelines recommend continuing anticoagulation indefinitely after ablation based on stroke risk factors rather than ablation success, but these recommendations are based on limited evidence from small, nonrandomized studies. Since catheter ablation is not 100% curative and AF can recur without symptoms, stopping anticoagulation after the procedure may increase stroke risk. Conversely, continuing anticoagulation increases bleeding risk. Two recent randomized trials have examined this question.

In the ALONE-AF trial, an open-label, multicenter, randomized clinical trial, 840 patients (mean age 64 years, mean CHA₂DS₂-VASc score 2.1) with AF who had undergone catheter ablation and had no documented AF recurrence for at least one year were randomized to discontinuing oral anticoagulant therapy (n=417) or continuing it with direct oral anticoagulants (n=423). After two years, the primary outcome, a composite of stroke, systemic embolism, and major bleeding, occurred in 0.3% of the discontinue group versus 2.2% of the continue group (absolute difference, -1.9 percentage points [95% CI, -3.5 to -0.3]; P=0.02). Ischemic stroke occurred in 0.3% and 0.8%, respectively, and major bleeding in 0% and 1.4% (P=0.03). Antiplatelet therapy was used in 8.6% of patients in the discontinue group versus 5.0% in the continue group. In the OCEAN trial, an open-label, randomized, blinded-outcome-assessment trial, 1,284 patients (mean age 66 years, mean CHA₂DS₂-VASc score 2.2) who had undergone successful catheter ablation for AF at least one year earlier were randomized to rivaroxaban 15 mg daily (n=641) or aspirin 70 to 120 mg daily (n=643) and followed for three years. The primary outcome, a composite of stroke, systemic embolism, or new covert embolic stroke detected by MRI, occurred in 0.8% of the rivaroxaban group versus 1.4% of the aspirin group (relative risk, 0.56; 95% CI, 0.19 to 1.65; P=0.28). Stroke occurred in 0.8% and 1.1%, respectively. Fatal or major bleeding occurred in 1.6% of the rivaroxaban group versus 0.6% of the aspirin group (hazard ratio, 2.51; 95% CI, 0.79 to 7.95).

Both trials demonstrate that stroke rates are very low after successful ablation, with annualized stroke rates of approximately 0.3% to 0.4% in patients without documented AF recurrence. The ALONE-AF trial found that discontinuing anticoagulation was superior to continuing it, primarily due to reduced bleeding events without an increase in stroke risk. The OCEAN trial found no significant difference between rivaroxaban and aspirin for stroke prevention, but rivaroxaban was associated with more bleeding. These findings suggest that for patients with successful ablation and no documented AF recurrence, the stroke risk may be low enough that anticoagulation discontinuation or aspirin therapy may be reasonable alternatives to continued anticoagulation, particularly for patients concerned about bleeding risk. However, both trials emphasize the importance of regular rhythm monitoring to detect AF recurrence, as asymptomatic recurrences can occur. The criteria used in these studies for documenting successful ablation serve as a starting point for selecting patients who may be candidates for anticoagulation discontinuation or de-escalation.

• ALONE-AF trial definition of successful ablation: No documented atrial arrhythmia recurrence for at least one year after ablation. Atrial arrhythmia recurrence was defined as any documented episode lasting 30 seconds or longer for AF, atrial flutter, or atrial tachycardia, assessed using at least two sessions of 24- to 72-hour Holter monitoring and ECG monitoring, with at least one session performed within two months prior to enrollment.
• OCEAN trial definition of successful ablation: No clinical evidence of any atrial arrhythmia and no atrial arrhythmia lasting longer than 30 seconds on at least one 24-hour Holter monitor study between 2 and 6 months after the ablation procedure and on at least one 24-hour Holter monitor study at any time after 6 months after the ablation procedure. Additional 48-hour Holter monitoring was performed during the 2 months before enrollment.

• ALONE-AF trial [PubMed abstract]
• OCEAN trial [PubMed abstract]
• Atrial fibrillation review