03.17.2015

SAN DIEGO — Weight loss might eliminate atrial fibrillation (Afib) among overweight or obese individuals, particularly if the shed pounds don’t return, the LEGACY registry study showed.

People who lost at least 10% of body weight were six times more likely to be free from arrhythmia without antiarrhythmic medication at 5 years (rate 46% versus 13% with less than 3% weight loss, P<0.001).

The apparent benefits were partially offset among the half of people whose weight fluctuated by more than 5% over that period, Rajeev K. Pathak, MBBS, of Australia’s Royal Adelaide Hospital, and colleagues reported here at the American College of Cardiology annual meeting. Study results were simultaneously published in the Journal of the American College of Cardiology.

Freedom from atrial fibrillation regardless of medication use was 85% in the group that kept the weight off with less than 2% weight fluctuation compared with 59% among those whose weight shifted around in the 2% to 5% of body-weight range and 44% among those who fluctuated even more.

Both factors were significant independent predictors of Afib recurrence (P<0.001 for trend).

The study included 355 patients at a single heart rhythm disorder referral center who had Afib and a body mass index of 27 kg/m². They were offered weight management at a weight-loss clinic emphasizing a low-carbohydrate, low-fat diet, and exercise. Freedom from Afib was determined by 7-day Holter monitoring.

For the primary outcomes, Afib symptom burden and global well-being scores showed significantly greater improvements with greater weight loss (both P<0.001 for interaction). Similar associations were seen for structural remodeling measures.

The message from LEGACY “is of immense practical value to clinicians,” Prediman “PK” Shah, MD, director of cardiology at Cedars-Sinai Medical Center in Los Angeles, commented at an ACC press conference he moderated.

“It suggests that like coronary disease, it starts with lifestyle modification and the same is true with atrial fibrillation,” he said. “We can argue ‘What’s the mechanism?’ until kingdom come, but the fact is the association is very strong, that weight loss is associated with a reduced burden of atrial fibrillation and a robust magnitude of effect.”

Bernard Gersh, J MBChB, DPhil, of the Mayo Clinic in Rochester, Minn., agreed. Gersh was the discussant at the late-breaking clinical trial session where the findings were presented.

“Bottom line is this is a very simple strategy for people with atrial fibrillation. They must lose weight,” he told MedPage Today. “And I think we should really consider that before we do ablative procedures because their recurrence rate was markedly reduced. Wonderful study.”

The study “confirms some long-standing suspicions regarding the relationship between obesity and atrial fibrillation,” noted John Jarcho, MD, a heart failure specialist at Brigham and Women’s Hospital in Boston and a deputy editor of the New England Journal of Medicine.

However, he cautioned that these observational findings can’t confirm that losing weight actually caused the Afib to disappear.

“It is possible that people in this study who were more likely to lose a large amount of weight were also more likely to engage in other healthy behaviors,” he told reporters at a press conference where he served as discussant.

The only way to be certain is a trial, he said, which Pathak’s group is undertaking.