Improving Outcomes After AF Ablation in Obese Patients (OBESE-AF)

This is a prospective randomized clinical study designed to evaluate the roles of gut microbiota dysbiosis, adipose tissue biology, and post-ablation lifestyle intervention in patients with atrial fibrillation undergoing catheter ablation. Patients with paroxysmal or persistent atrial fibrillation who are scheduled to undergo catheter ablation at National Taiwan University Hospital will be enrolled after informed consent.

All participants will undergo standard-of-care catheter ablation and receive guideline-directed management for atrial fibrillation, including treatment of cardiovascular conditions, anticoagulation, and rate or rhythm control as clinically indicated. After the index ablation procedure, participants will be randomly assigned in a 1:1 ratio to either an intensive lifestyle modification program or usual care.

Participants assigned to the intensive lifestyle modification group will receive dietary counseling for weight reduction when indicated and an exercise-based cardiac rehabilitation program. The rehabilitation program will include supervised aerobic exercise and resistance or strength training, together with recommendations for home-based moderate-intensity walking exercise. Participants assigned to the usual care group will continue their usual lifestyle and receive standard post-ablation clinical follow-up.

The study will collect clinical characteristics, procedural data, rhythm follow-up data, biological samples, and imaging-based measurements. Gut microbiota dysbiosis will be assessed using stool specimens and high-throughput sequencing of the V3 and V4 hypervariable regions of 16S rRNA. Adipose tissue biology will be evaluated using computed tomography to quantify the amount and distribution of adipose tissue, including epicardial, paracardial, pericardial, visceral, and subcutaneous fat. Serum biomarkers related to inflammation and fibrosis, including hs-CRP, TNF-alpha, IL-1 beta, ST2, and galectin-3, will also be assessed.

Cardiac structural remodeling will be evaluated using cardiac computed tomography and echocardiography, including left atrial size, left ventricular mass, left ventricular ejection fraction, and parameters of left ventricular diastolic function. Electrophysiological remodeling of the left atrium will be assessed using three-dimensional voltage mapping during the ablation procedure, including the extent of scar and low-voltage zones.

Participants will undergo rhythm follow-up after catheter ablation using 12-lead electrocardiography, continuous patch electrocardiographic monitoring, and Holter monitoring as clinically indicated. The study will evaluate AF-free survival after the blanking period and will explore whether the post-ablation lifestyle intervention modifies ablation outcomes, body mass index, metabolic parameters, gut microbiota dysbiosis, adipose tissue biology, cardiac structural remodeling, and electrophysiological remodeling.