Research Highlights:

• Successful catheter ablation resulted in a low risk of stroke associated with atrial fibrillation (AFib), a type of irregular heart rhythm, according to an international study.
• Researchers said these findings may suggest that ongoing blood-thinning medication may not be needed after an ablation procedure.
• While catheter ablation is known to reduce the occurrence of AFib, it’s been unclear if it also reduces the increased stroke risk associated with the AFib.
• Note: This trial is simultaneously published today as a full manuscript in the peer-reviewed scientific journal New England Journal of Medicine.

Embargoed until 2:15 p.m. CT/ 3:15 p.m. ET, Saturday, Nov. 8, 2025

NEW ORLEANS, LA - November 8, 2025 (NEWMEDIAWIRE) - A minimally invasive heart procedure to correct irregular heart rhythms called catheter ablation may reduce the risk of stroke enough that some patients can discontinue blood thinners, according to a preliminary late-breaking science presentation today at the American Heart Association’s Scientific Sessions 2025. The meeting, Nov. 7-10, in New Orleans, is a premier global exchange of the latest scientific advancements, research and evidence-based clinical practice updates in cardiovascular science.

In the OCEAN Randomized Trial, researchers evaluated whether long-term oral anticoagulation is needed after successful ablation in people with an increased risk of stroke. An international group of researchers enrolled nearly 1,300 adults at multiple sites in several countries and followed their progress for three years after they had ablation to treat atrial fibrillation (AFib). Participants included people with no evidence of irregular heart rhythm recurrence and those with moderate to high stroke risk, which calls for long-term blood thinners.

According to the American Heart Association, AFib increases stroke risk by five-fold and can lead to blood clots, heart failure and death. An estimated five million people in the U.S. live with AFib, and it is predicted that more than 12 million people will have it by 2030, per the Association’s 2025 Heart Disease and Stroke Statistics report.

The condition can be treated with catheter ablation, a minimally invasive nonsurgical procedure that can eliminate the electrical triggers for AFib and prevent the irregular rhythms from returning. Current American Heart Association/American College of Cardiology guidelines recommend continuing blood-thinning medications in moderate-to-high risk individuals to prevent stroke, even after a successful ablation.

“We know that ablation for AFib is effective, however, we did not know if elimination of the arrhythmia also reduces the long-term risk of stroke,” said study author Atul Verma, M.D., director of cardiology at McGill University Health Centre in Montreal. “Many people who have undergone successful ablation will ask ‘Can I stop my blood thinners?’ Until now, we have told them to continue taking blood thinners because we had insufficient evidence to suggest it was safe to stop. So, it was important to find out if successful ablation could allow discontinuing blood thinners.”

Researchers prescribed half of the eligible participants 75-160 mg of aspirin (a mild antiplatelet) daily. The other half were prescribed 15 mg daily of oral rivaroxaban, a potent blood thinner.

The study found that prescribing the blood thinner rivaroxaban after catheter ablation to treat AFib offered no major difference in stroke protection than those taking aspirin and increased bleeding risk compared to aspirin. Specifically:

• The three-year risk of stroke, including a covert stroke, which is only detectable on brain imaging, was 0.8% in the rivaroxaban group and 1.4% in the aspirin group.
• The annual stroke risk was 0.3% in the rivaroxaban arm and 0.7% in the aspirin arm —variances not significant enough to indicate a notable difference between groups.
• There were no notable differences in major or fatal bleeding complications whether people took rivaroxaban or aspirin.
• However, clinically relevant, non-major bleeding (bleeding serious enough to cause people to seek medical attention) was 5.5% for rivaroxaban versus 1.6% for aspirin, or about 3.5 times more likely with rivaroxaban.

“In essence, catheter ablation for AFib reduced the recurrence of atrial fibrillation and can also reduce the risk of stroke associated with this common heart rhythm condition,” Verma said. “With the notably increased bleeding risk associated with rivaroxaban, we concluded that the anticoagulant did not offer any advantages in comparison to aspirin for reducing what we found to be a low stroke risk in these individuals. Now, we can advise patients that it may be safe to stop blood thinners, even if they have a moderate stroke risk.”

Study details, background and design:

• The study included 1,284 adults, average age 66 years, 71% men, who on average were within 16.4 months of their last ablation procedure.
• Participants were enrolled in health care centers in Canada, Australia, Germany, Belgium, Israel and China between March 30, 2016, and July 25, 2022, and their progress was followed for three years.
• Researchers used the CHA2DS2-VASc score, which measures a person with AFib’s risk of stroke on a scale of 0 to 9 based on the presence of other conditions, such as heart failure, hypertension, diabetes, prior stroke or vascular disease, plus their age and sex. In this study, the average CHA2DS2-VASc score at enrollment was 2.2, and nearly 32% of participants had a score of 3 or higher, which is considered high risk.
• Researchers collected data on stroke, systemic embolism and bleeding events, and all participants had brain magnetic resonance imaging (MRI) at enrollment and again at three years.
• Participants were randomly assigned to one of two groups for the duration of the trial: aspirin 75-160 mg daily or rivaroxaban 15 mg daily.
• Data was analyzed between the two groups: rivaroxaban (anticoagulation) vs. aspirin (antiplatelet).

Among the study’s limitations, only a small percentage of participants a CHA2DS2-VASc score of 4 or higher. As a result, the findings may not be relevant to higher-risk individuals.

Co-authors, funding information and disclosures are listed in the abstract.

Statements and conclusions of studies that are presented at the American Heart Association’s scientific meetings are solely those of the study authors and do not necessarily reflect the Association’s policy or position. The Association makes no representation or guarantee as to their accuracy or reliability. Abstracts presented at the Association’s scientific meetings are not peer-reviewed, rather, they are curated by independent review panels and are considered based on the potential to add to the diversity of scientific issues and views discussed at the meeting. The findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.

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Additional Resources:

• Multimedia is available on the right column of the release link.
• View the abstract in the American Heart Association Scientific Sessions 2025 Online Program Planner
• American Heart Association news release: New research finds 62% of AFib patients were unaware of the condition before diagnosis (Sept. 2025)
• American Heart Association health information: Fact Sheet: What Is Atrial Fibrillation?
• American Heart Association health initiative: My AFib Experience®
• About Scientific Sessions 2025
• For more news at AHA Scientific Sessions 2025, follow us on X @HeartNews,#AHA25

About the American Heart Association

The American Heart Association is a relentless force for a world of longer, healthier lives. Dedicated to ensuring equitable health in all communities, the organization has been a leading source of health information for more than one hundred years. Supported by more than 35 million volunteers globally, we fund groundbreaking research, advocate for the public’s health, and provide critical resources to save and improve lives affected by cardiovascular disease and stroke. By driving breakthroughs and implementing proven solutions in science, policy, and care, we work tirelessly to advance health and transform lives every day. Connect with us on heart.org, Facebook, X or by calling 1-800-AHA-USA1.

For Media Inquiries and American Heart Association Expert Perspective:

American Heart Association Communications & Media Relations in Dallas: 214-706-1173;ahacommunications@heart.org

Bridgette McNeill: bridgette.mcneill@heart.org

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