In a new study, patients with atrial fibrillation who were overweight or obese when they underwent ablation to correct their abnormal heart rhythm were more likely to experience a return of a-fib than folks who were not. Photo by bikeriderlondon/Shutterstock
If you’re one of the millions of people with a common heart rhythm disorder called atrial fibrillation (a-fib), losing weight before treatment may increase the odds that your a-fib doesn’t come back.
In a new study, patients with a-fib who were overweight or obese when they underwent ablation to correct their abnormal heart rhythm were more likely to experience a return of a-fib than folks who were not.
A-fib occurs when the upper chambers of the heart quiver chaotically, causing a fast and irregular heartbeat. Left undiagnosed or untreated, it dramatically raises risk for stroke and heart failure. Ablation involves burning or freezing a small portion of the heart to create a scar and prevent the spread of abnormal electrical impulses.
“Overweight patients have a higher risk of recurrent a-fib after ablation compared to normal-weight patients, and the risk of recurrent a-fib increases incrementally by increasing body mass index,” said study author Dr. Jacob Tønnesen, a cardiologist at Herlev-Gentofte University Hospital in Hellerup, Denmark.
“Aggressive weight management, pre-ablation, in overweight patients could potentially provide substantial benefits and improve short- and long-term outcomes after ablation,” he said.
Exactly how much weight a person with a-fib should lose before ablation therapy isn’t known yet.
“One study found that a weight loss of 10% leads to a significantly lowered burden of atrial fibrillation, but further studies on this are warranted,” Tønnesen said.
For the study, more than 9,200 people in Denmark who underwent a first-time procedure for a-fib were divided into five groups. The groups were based on their body mass index (BMI), an estimate of body fat based on height and weight: underweight, normal weight, overweight, obese and morbidly obese. Researchers then compared BMI categories to risk of an a-fib recurrence.
Compared to folks with a normal BMI, the likelihood of a-fib at one year was 19% higher in the overweight group 22% higher in the obese group, and 32% in the morbidly obese group.
The same pattern was also seen after five years, the study showed. There was no difference in relapse risk among folks who were underweight or normal weight. The findings held even after researchers controlled for other factors known to increase the risk of a-fib coming back.
Being overweight or obese is as much of a risk for a-fib returning as heart failure, chronic obstructive pulmonary disease (COPD) and high blood pressure — all of which are typically treated in people with a-fib, Tønnesen said.
The study was presented Monday at a meeting of the European Society of Cardiology, in Copenhagen, Denmark, and online. Findings presented at medical meetings are typically considered preliminary until published in a peer-reviewed journal.
Experts not part of the study agree that losing weight before treatment for a-fib greatly increases the odds of success.
People who are overweight or obese and need ablation to correct a-fib are always counseled to lose weight first, said Dr. Rachel-Maria Brown Talaska, director of inpatient cardiac services at Lenox Hill Hospital in New York City.
“A number of studies indicate that weight loss is associated with a reduction in atrial fibrillation severity, improving symptoms and recurrence rates,” she said.
This makes sense from a heart structure standpoint. “Weight loss has been associated with a reduction in the size of the left atrium, which tends to stretch with atrial fibrillation, with this larger size predisposing to more bouts of atrial fibrillation in the future,” Brown Talaska said.
Dr. Deepak Bhatt, executive director of interventional cardiovascular programs at Brigham and Women’s Hospital Heart and Vascular Center in Boston, agreed.
“This is a large and well-done study which adds further evidence that people with atrial fibrillation who are overweight should try to lose weight,” he said.
Prior studies have made it fairly clear that excess weight contributes to the risk of developing a-fib, Bhatt said.
“For people who already have the condition, the risk of recurrence does seem to be lower if they lose weight, especially if their atrial fibrillation is so problematic that they need procedures, as in this study,” he said.
The U.S. National Heart, Lung, and Blood Institute has