ORLANDO (FRONTLINE MEDICAL NEWS) – Excess body weight exerts a major negative impact on the likelihood of remaining free of atrial fibrillation long term after an ablation procedure, according to a new set of data and a review of published studies.

“Just losing 3 pounds can dramatically improve the long-term success of an ablation when compared to a weight gain,” reported John D. Day, MD, medical director, Intermountain Heart Rhythm Specialists, Salt Lake City, at the annual International AF Symposium.

Relying on a barrage of published studies, including one for which he was a coauthor ( J Interv Card Electrophysiol. 2016 Sep;46[3]:259-65 ), Dr. Day provided evidence that obesity increases the risk of developing atrial fibrillation (AF), that losing weight by any means, including bariatric surgery, reduces the risk of developing AF, and that losing weight after developing AF can increase the likelihood of achieving and remaining in remission.

“As BMI goes up, long-term success in controlling AF goes down. The difference at 1 year may not be a big deal, but if you follow patients for a long time, weight control is a very big deal,” Dr. Day advised. He emphasized repeatedly, “We are just talking about a few pounds” for a favorable effect.

New data presented at the meeting supported the message. In the study, ablation outcomes in relationship to body mass index (BMI) were evaluated in 2,715 AF patients undergoing 3,742 ablations. Patients were stratified into five groups by BMI: less than 25 kg/m2, 25 to less than 30; 30 to less than 35; 35 to less than 40, and at least 40.

As BMI increased from less than 25 to at least 40, there were significant increases in left atrial size (P less than .005), CHADS2 scores (P = .002), persistent AF (P less than .0001), and longstanding AF (P less than .0001). Unlike persistent and long-term AF, rates of paroxysmal AF fell (48% to 16.3%; P less than .0001).

“In multivariate analysis, BMI of at least 35 predicted worse ablation outcomes (P = .036),” reported Roger A. Winkle, MD , Silicon Valley Cardiology, Palo Alto, Calif. “For the entire cohort, when BMI was at least 35, the 5-year ablation freedom from AF fell from 70% to 57% (P = .0001).”

Not surprisingly and consistent with other published reports, increasing BMI was associated with increases in many of the key risk factors for AF in the study.

Specifically, as BMI increased from less than 25 to at least 40, the proportion of patients with cardiomyopathy climbed from 7.6% to 12.4% (P less than .001), hypertension climbed from 41% to 72.9% (P less than .0001), diabetes climbed from 4.3% to 23.3% (P less than .0001), and sleep apnea climbed from 7.0% to 46.9% (P less than .0001).

Dr. Day cited the LEGACY trial as one of the most influential studies associating weight loss with a reduction in AF burden ( J Am Coll Cardiol. 2015 May 26;65[20]:2159-69 ). In that study, weight loss of at least 10% resulted in a sixfold increased likelihood of AF-free survival. Independent of AF, Dr. Day also pointed out that the sense of well-being among patients who achieved weight loss improved 200%.

Recognizing that major weight loss is difficult to achieve, Dr. Day repeatedly returned to the theme of weight control.

He cited one study in which AF patients were randomized to a weight loss program or usual care. In the usual care group, which included physician advice to lose weight, there was a small but significant weight loss. Even though the effect of that weight loss on AF burden was a fraction of that achieved in the group that achieved greater reductions in weight on active management, it, too, was significant, according to Dr. Day.

“Even brief physician advice can have a meaningful influence on waist circumference,” said Dr. Day, who urged physicians to inform their AF patients about the benefits of weight loss. Failing to do so might deprive patients of achieving the very modest reductions in weight loss required to improve their likelihood of freedom from AF, he added.

Dr. Winkle had no relevant financial relationships. Dr. Day reported a financial relationship with St. Jude Medical.


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