Weight Loss Reduces Atrial Size, Pericardial Fat in AF Patients

March 02, 2015

SYDNEY, AUSTRALIA — For patients with paroxysmal and persistent atrial fibrillation (AF), losing weight resulted in a significant reduction in pericardial adipose tissue and favorable changes in cardiac structure, according to the results of a new study[1].

The weight-loss intervention resulted in a significant reduction in the right and left atrial volumes and a significant decrease in myocardial mass, report investigators.

Led by Dr Hany Abed (University of Sydney, Australia) and published online February 21, 2015 in the American Heart Journal, the study included 69 patients who underwent baseline and 12-month cardiac magnetic resonance (CMR) imaging as part of a larger randomized, clinical trial testing the effects of a weight-loss intervention on AF burden. The main study results, published in the Journal of the American Medical Association in 2013 and reported by heartwire , showed that weight loss and the management of cardiometabolic risk factors could significantly reduce the burden of AF in obese and overweight subjects.

Regarding the dietary intervention, individuals randomized to weight loss consumed a low-calorie diet (1200 kcal/day), were prescribed an exercise program, and received counseling and behavioral coaching. They lost 15.0 kg over the 12-month period compared with just 3.9 kg in the control arm.

In the weight-loss intervention arm, CMR imaging showed these patients had a significantly larger decline in pericardial adipose tissue and a significantly larger reduction in myocardial mass compared with the control arm. Right and left atrial volumes also declined significantly.

The results, according to the Australian researchers, provide a mechanism of action in support of weight loss for the reduction of AF burden in obese and overweight individuals. Pericardial adipose tissue has been previously recognized as a risk factor for incident AF as well as AF severity. It has also been linked with worse AF outcomes, they add.

"Left atrial enlargement is strongly associated with AF in both obese and nonobese individuals, so the reduction in left atrial volume observed is also consistent with our previous finding of reduced AF burden with a weight-management intervention," write Abed and colleagues.

Long-term follow-up results from a look at the effect of documented weight loss on Holter-documented AF burden are scheduled for presentation March 16 at the American College of Cardiology 2015 Scientific Sessions. The observational study, called Long-Term Effect of Goal Directed Weight Management on an Atrial Fibrillation Cohort: A 5-Year Follow-Up Study (LEGACY), had followed an estimated 356 overweight or obese men and women younger than 65 with paroxysmal or persistent AF.

The authors report no relevant financial relationships.


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