Metformin Shows Promise in Reducing AFib Recurrence After Ablation in Overweight and Obese Patients

Adults with atrial fibrillation and obesity or overweight who took the diabetes medication metformin after a rhythm correction procedure were more likely to stay free of AFib episodes for a year according to research presented at the American Heart Association's Scientific Sessions 2025. The Metformin as an Adjunctive Therapy to Catheter Ablation of Atrial Fibrillation study analyzed 99 adults with AFib and obesity or overweight to determine whether adding metformin to standard care after catheter ablation would be beneficial.

During the year after ablation, the analysis found 78% of the metformin group versus 58% of the usual-care group had no episodes of AFib lasting 30 seconds or more. The metformin group also had fewer patients who needed a repeat ablation or electric shock to restore normal heart rhythm during an AFib episode at 6% versus 16% respectively. Antiarrhythmia medications were used after ablation in only 8% of patients in the metformin group compared to 18% in the usual care group.

Lead author Amish Deshmukh, clinical assistant professor of medicine at the University of Michigan, noted that treatment with metformin in people with obesity who do not have diabetes and are undergoing AFib ablation seems to lower the likelihood of recurrent AFib or atrial arrhythmias after a single procedure. Weight changes were minimal in all participants, consistent with prior studies of metformin use in people without diabetes, suggesting weight loss was not the primary mechanism for the observed benefits.

The study raises questions about whether other medications for diabetes and weight loss, such as GLP-1 receptor agonists, may have similar benefits in adults without diabetes with AFib and obesity. According to the American Heart Association's 2025 Heart Disease and Stroke Statistics available at https://www.heart.org, AFib currently affects more than 6 million people in the U.S., making this research particularly relevant given the prevalence of both conditions.

The study was conducted at the University of Michigan between 2021 and 2025 and included adults with an average age of 63 years, with 70% categorized as obese and the rest as overweight. All participants received ablation and were randomly selected to receive either usual care or usual care plus metformin. After a 3-month period to allow for healing after ablation and increasing metformin to the maximum dose, patients were monitored for recurrence of AFib lasting at least 30 seconds.

Researchers calculated the AFib burden based on information from clinical monitoring, handheld monitors, pacemakers and defibrillators over one year. A significant limitation noted was that 12 of 49 participants stopped taking metformin due to side effects or because they felt better or didn't want to add another medication to their regimen. The study authors suggest conducting larger studies to investigate metformin and other diabetes treatments for AFib management.