Adults with atrial fibrillation (AFib) who are not diabetic but are overweight and took the diabetes medication metformin after a rhythm-correction procedure had decreased risk of AFib episodes for a year. Weight loss would usually be a confounder, since lifestyle changes such as that are often a big help, but in the data sample the weight changes were low.

Atrial fibrillation is commonly known as irregular and rapid heartbeat. It is the most common heart rhythm disorder and therefore linked to blood clots, stroke, heart failure and every other heart-related condition. Metformin was invented in the 1950s and made available in the United States after FDA approval in 1994. It helps control blood sugar levels and is often the initial treatment in people with lifestyle diseases like Type 2 diabetes.



Because it has decades of safety data, off-label use might be easier to obtain than the onerous FDA process for a new medication. It works better than other anti-diabetic agents and exploratory work has found that metformin directly affects heart cells and reduced irregular heart rhythms in animals. Yet animals are not little people, so the Metformin as an Adjunctive Therapy to Catheter Ablation of Atrial Fibrillation (META-AF) study enrolled 99 adults (average age 63, all overweight, 70% obese) with AFib and obesity or overweight to determine whether adding metformin to standard care after a catheter ablation procedure would be beneficial. Participants received ablation and then were randomized to get usual care (eat less, exercise more) or usual care plus metformin.

They found that 78% of the metformin group had no episodes of AFib lasting 30 seconds or more versus 58% of the usual-care group. The metformin group also had fewer patients (6%) who needed a repeat ablation or electric shock to restore a normal heart rhythm during an AFib episode than the control group (16%) and less frequent AFib episodes during heart rhythm monitoring compared to the usual care group (8% versus 16%, respectively).

It is almost certain researchers will want to see if GLP-1 receptor agonists used as diet injections in people without diabetes have similar benefits and side effects in adults with AFib.