Obesity is well known to promote atrial fibrillation (AF) and catheter ablation it can drastically reduce the prevalence of AF. But assigning patients to a structured obesity reduction program after AF ablation may not improve the effect of treatment on AF burden, a new randomized trial suggests.
Of 133 patients with persistent or paroxysmal symptomatic AF with a body mass index (BMI) between 30 and 40 kg / m2 , those assigned to the post-establishment obesity reduction program lost weight but did not benefit from less AF, compared to those who received standard care.
However, there were signs that the weight loss regimen (which included physical training, dietary advice, and other items) may have caused the risk of recurrence of AF for patients with persistent AF, but not for those with persistent AF. the paroxysmal form.
This seemed especially true for those who entered the study of three centers with persistent AF and who also improved their exercise capacity during the twelve months of the trial. The risk of recurrence of AF fell by 23% compared with those with paroxysmal AF.
This post hoc finding shows the “impact and relevance” of lifestyle-related risk factor modification “as an important complement” in FA management, noted Stephan Willems, MD, Asklepios Klinik St . Georg, Hamburg, Germany, when he presented findings on April 25 in the virtual European Heart Rhythm Association 2021 congresses. They were published the same day a EP Europace.
The study, called Supervised Test for Reducing Obesity in Atrial Fibrillation (BLACK-OFF), showed similar and significant drops in AF load in both treatment groups, thus demonstrating that AF ablation is “safe and successful” in obese patients, Willems said.
It should be noted that most of the patients in the trial had multiple risk factors for AF, in addition to obesity. And all participants were evaluated, regardless of treatment assignment, and offered therapy as needed for high blood pressure, disturbed sleep, and diabetes. They all received one implantable loop recorder (ILR) before ablation to control rhythm abnormalities.
“The first of its kind”
SORT-AF follows numerous observational studies, mainly, suggesting that weight loss, exercise, and risk factor modification protocols may alleviate the symptoms and prevalence of AF. They include him LEGACY, INVESTMENT, i CARDIO-FIT studies, along with ARREST-AF, in which patients who followed an intensive risk factor management program showed significant improvements in symptoms, success of AF ablation, and FA-free survival.
However, SORT-AF “is the first of its kind to evaluate the effect of a structured weight loss program after an ablation procedure in patients with paroxysm or persistent atrial fibrillation”observed John Camm, MD, St Georges University London, as a guest speaker following Willems’ presentation.
The post hoc finding of the “trial” in those with persistent AF, he said, could have more weight if the analysis of the AF recurrence subgroup had been defined prospectively.
Even if previously specified, Camm said, it is “difficult” to accept a secondary outcome benefit when a trial does not show a significant effect on the primary outcome.
SORT-AF was “a good attempt to demonstrate the potential value” of post-establishment weight loss. Although he did not demonstrate this benefit, he said, at least the trial proposes that this weight loss may prevent recurrences in patients undergoing persistent AF ablation.
Explanation of the negative finding
“Previous studies have shown that the level of weight loss associated with the greatest reduction in atrial fibrillation recurrence is 10% of basal body weight,” noted T. Jared Bunch, MD, University of Utah, Salt Lake City. theheart.org | Cardiology Medscape.
The study intervention group lost 4.5% of body weight on average, and the control group less than 1.0%.
SORT-AF “shows that a formal multispecialty program after ablation can lead to sustained weight loss. However, the program may need modifications to improve the likelihood of achieving a weight loss goal greater than 10 % “, said Bunch, who was not part of the trial.
“The success of weight loss may have been too small to show an effect on the FA load,” the published report agrees. “We believe this is an important factor for which the analysis of intent to treat was negative.”
Other potential explanations, he says, include non-compliance in a third of those assigned to the weight loss program. The authors also propose that the FA load could have decreased further “if weight loss had been achieved at the time of ablation and not afterwards.”
Bunch also noted that patients in both groups achieved similar reductions in blood pressure for 12 months, “despite increased weight loss in the intervention group.” High blood pressure “often causes the onset and progression of atrial fibrillation,” so its management in the usual care group “may have masked some of the benefits” of weight loss in the group. of intervention.
In patients who receive AF ablation but do not achieve sustained weight loss, he said, “aggressive management of blood pressure can offset some of the risks.”
An advantage for those with persistent AF?
The 133 patients in the trial, of whom 57% had persistent AF and the rest had paroxysmal AF, had a mean age of 60 years and 38% were female. After full pre-ablation assessment, ILR implantation, and AF ablation by pulmonary vein isolation, Willems noted, 67 were assigned to the post-tabulation structured weight reduction program and 66 to routine care.
The intervention included “medical advice on nutrition and regular physical training” along with cognitive behavioral therapy, he noted.
As described in the publication SORT-AF, the weight reduction program “took place in a department specializing in obesity as an interdisciplinary multimodal concept under the supervision of a physician specializing in endocrinology.”
The program default rate was 19% after 3 months, 21% at 6 months, and 33% at 1 year. The average BMI of the whole intervention group fell modestly but significantly from 34.9 to 33.4 kg / m2 (Pg <.001), compared with no change in the control group.
The main final criterion, FA load at 12 months, excluding a 3-month emptying period, was similar in the two groups. However, the burden of AF had plummeted in both groups, from 21.6% to 3.79% in the intervention group and from 22.4% to 4.21% in the group that received standard care (Pg <.001 for the two differences).
The decrease in BMI of patients assigned to the intervention correlates with fewer recurrences of AF among patients initially with persistent AF than with paroxysmal (Pg = 0.032). But the AF recurrence risk ratio (HR) for those with persistent AF and improved exercise capacity was 0.77 (95% CI, 0.64 – 0.93).
This finding, Bunch said, “supports weight reduction as a strategy.” In patients with paroxysmal AF, who generally have a lower AF load, he noted, the lack of weight loss effect “is probably due to the figures entered in the study, which affect the ability to determine any difference. “.
SORT-AF received support from a research grant from Abbott Medical GmbH. Willems reveals the receipt of Abbott grants and personal fees and personal fees from Boston Scientific, Boehringer Ingelheim, Bristol Myers Squibb, Bayer Vital, Acutus and Daiichi Sankyo. The report contains disclosures for the other authors.
European Heart Rhythm Association (EHRA) 2021: Innovative technology. Supervised obesity reduction trial for patients with AF ablation: results of the SORT-AF trial. Filed April 25, 2021.
EUROPAC. Published online April 25, 2021. Summary