Current guidelines for management of atrial fibrillation (AF) recommend continuation of oral anticoagulation (OAC) following successful catheter ablation of AF for patients deemed at elevated thromboembolic risk.^1,2 These are based primarily on nonrandomized, observational studies. Within the previous year, two randomized clinical trials have been published (ALONE-AF [Anticoagulation One Year After Ablation of Atrial Fibrillation in Patients With Atrial Fibrillation] and OCEAN [Optimal Anticoagulation for Enhanced Risk Patients Post-Catheter Ablation for Atrial Fibrillation]), which may redefine the approach to OAC in the post-ablation patient.

ALONE-AF Trial

In the ALONE-AF trial,³ 840 adult patients across 18 hospitals in South Korea with ≥1 stroke risk factor and no documented atrial arrhythmia for ≥1 year after AF ablation were randomized to OAC continuation and discontinuation arms. Atrial arrhythmia was defined as any documented episode lasting ≥30 seconds on one of two 24- to 72-hour Holter monitors obtained every 6 months in the year following catheter ablation. The population studied was predominantly male and largely included patients with paroxysmal AF.

ALONE-AF found that the risk of a primary outcome of stroke, systemic embolism, and major bleeding was lower in the discontinuation arm compared with the continuation arm, driven largely by a reduction in major bleeding events. In addition, this trend persisted even among patients with CHA₂DS₂-VASc scores ≥4. Notably, transient ischemic attacks were excluded from the primary outcome. Overall, ALONE-AF was limited by small event sizes and the role of major bleeding in biasing the net clinical outcome; however, this trial provided much needed randomized data on a commonly faced clinical scenario.

OCEAN Trial

The OCEAN trial now provides additional insight on the prospect of discontinuing OAC in the post-catheter ablation population.⁴ The study included 1,284 patients without documented AF ≥1 year after catheter ablation and with ≥1 stroke risk factor. Similar to the ALONE trial, monitoring for AF recurrence was performed using two 24-hour Holter monitors, one occurring between 2 and 6 months post-ablation and the second any time after 6 months post-ablation. Patients were randomized to receive either aspirin or rivaroxaban. The patient population also was predominantly male with paroxysmal AF.

Unlike in ALONE-AF, the primary outcome in OCEAN did not include major bleeding, but rather included stroke, systemic embolism, or new covert embolic stroke detected on mandatory magnetic resonance imaging (MRI) of the brain performed at 3 years. Enrollment in the trial was prematurely stopped in 2022 due to high likelihood that the trial would not show a benefit of rivaroxaban for the primary outcome and due to higher risk of nonmajor bleeding in the rivaroxaban arm.

Although the OCEAN trial also had low event rates, calling into question its statistical power, the requirement of the mandatory MRI showed relatively few new infarcts, which provides some reassurance regarding validity. The OCEAN trial was limited by lack of a true placebo arm, new (lower) rivaroxaban dosing, and long-term monitoring for AF recurrence. Finally, an additional limitation to note is that OCEAN was designed and powered as a superiority study to show benefit in favor of rivaroxaban; thus, failure to meet the primary endpoint may not in and of itself conclusively demonstrate noninferiority of the aspirin arm.

Perspective

At the present time, catheter ablation of AF is offered to patients for improvement in quality of life and is a superior option for maintaining sinus rhythm over antiarrhythmic medications. ALONE-AF and OCEAN trials may provide the basis for discontinuation of OAC following successful catheter ablation of AF, although notably in a patient population who underwent catheter ablation before the era of pulsed field ablation.

It appears evident that should future guidelines reflect results of these trials, appropriate patient selection for discontinuation of OAC is of paramount importance. Although a low CHA₂DS₂-VASc score or maintenance of sinus rhythm does not fully eliminate stroke risk in patients with a history of AF, critical insights such as those provided in these trials will continue to inform risk-benefit conversations regarding OAC discontinuation in post-AF ablation patients.

References

1. Writing Committee Members, Joglar JA, Chung MK, et al. 2023 ACC/AHA/ACCP/HRS guideline for the diagnosis and management of atrial fibrillation: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. J Am Coll Cardiol. 2024;83(1):109-279. doi:10.1016/j.jacc.2023.08.017
2. Tzeis S, Gerstenfeld EP, Kalman J, et al. 2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation. Europace. 2024;26(4):euae043. doi:10.1093/europace/euae043
3. Kim D, Shim J, Choi EK, et al. Long-term anticoagulation discontinuation after catheter ablation for atrial fibrillation: the ALONE-AF randomized clinical trial. JAMA. 2025;334(14):1246-1254. doi:10.1001/jama.2025.14679
4. Verma A, Birnie DH, Jiang C, et al. Antithrombotic therapy after successful catheter ablation for atrial fibrillation. N Engl J Med. 2026;394(4):323-332. doi:10.1056/NEJMoa2509688