Effect of Complex Weight-Reducing Interventions on Rhythm Control in Obese Individuals with Atrial Fibrillation Following Catheter Ablation: A Study Protocol.

INTRODUCTION Obesity and atrial fibrillation (AF) pose a significant burden on healthcare systems worldwide. Reduction of body weight has been documented to reduce the risk of AF. Little is known about the effect of different weight-reducing interventions including bariatric surgery in obese individuals on the risk of arrhythmia recurrence following catheter ablation (CA) for AF, and about the pathophysiological mechanisms linking these two conditions. METHODS The Effect of complex weigHt-reducing interventiOns on rhythm control in oBese subjects wITh Atrial Fibrillation (HOBIT-AF) is a single-blinded, parallel-group randomised controlled trial with 18-month follow-up to assess the effect of complex weight-reducing interventions supported by the use of smart technologies and bariatric surgery on the arrhythmia burden in obese individuals following CA for AF. One hundred and sixty individuals (age 18-70 years, body mass index ≥ 30 kg/m2) will be randomised in a 1:1 fashion to undergo a structured weight reduction programme and sleeve gastrectomy (when indicated and preferred by the patient) aiming to achieve greater than 10% weight reduction from baseline (intervention group) or standard post-ablation medical care (control group). Two-week continuous ECG monitoring will be used 3 and 18 months after CA to assess the arrhythmia burden. Other investigations will include transthoracic echocardiography with quantification of epicardial adipose tissue, and markers of low-grade inflammation and circulating adipokines. PLANNED OUTCOMES The main objective is to assess the effect of complex weight-reducing interventions on the arrhythmia burden and quality of life. Subgroup analyses to identify patient subgroups preferentially benefiting from weight loss related to a decrease in arrhythmia burden will be performed. Exploratory objectives will include investigation of potential mechanisms linking weight reduction with amelioration of arrhythmia burden such as changes in markers of low-grade inflammation, circulating adipokines, cytokines, monocytes or reduction of epicardial adipose tissue volume. TRIAL REGISTRATION NCT04560387.