Abstract 4136804: Effect of Obesity on Arrhythmia Recurrence and Complications following Pulmonary Vein Isolation for Paroxysmal Atrial Fibrillation in the REAL-AF Registry

Introduction: Obesity is an important risk factor for atrial fibrillation and its prevalence in the United States is rising. The effect of obesity on outcomes following pulmonary vein isolation in a contemporary setting has not been extensively evaluated. Research Questions: - Is higher body mass index (BMI) associated with increased risk of atrial arrhythmia recurrence following pulmonary vein isolation? - Is higher BMI associated with increased risk of post-procedural complications? Method: - The REAL-AF (Real-world Experience of Catheter Ablation for the Treatment of Symptomatic Paroxysmal and Persistent Atrial Fibrillation; ClinicalTrials.gov Identifier: NCT04088071) Registry is a multicenter, prospective observational registry of patients undergoing radiofrequency catheter ablation of atrial fibrillation. We included 2666 patients with paroxysmal atrial fibrillation undergoing index ablation from January 2018 through April 2023. We excluded patients with missing covariates. - The primary outcome was freedom from atrial arrhythmia following ablation. Rhythm monitoring was standardized using patch monitor at 6 month and 1 year. Time-to-event analysis was performed using a 3-month blanking period. Results: - Baseline characteristics are shown in Table 1. The median follow-up was 382 days (IQR: 363-410). - There was a trend toward higher rate of atrial arrhythmia following ablation for patients in the highest BMI group compared with the reference group (BMI<25) ( BMI≥40: HR = 1.41 (0.94-2.12), p= 0.092). There was no difference in the rate of atrial arrhythmia for other BMI groups ( BMI 25 - <30: HR = 0.90 (0.65-1.23), p = 0.5; BMI 30 - <35: HR = 0.89 (0.64-1.23), p = 0.5; BMI 35 - <40: HR = 0.87 (0.57-1.32), p = 0.5). This trend persisted following adjustment for baseline covariates ( BMI 25 - <30: HR = 1.01 (0.77-1.33), p > 0.9; BMI 30 - <35: HR = 0.97 (0.72-1.32), p = 0.9; BMI 35 - <40: HR = 1.01 (0.66-1.55), p > 0.9; BMI≥40: HR = 1.57 (0.96-2.57), p =0.071). - First-pass isolation rates progressively decreased with higher BMI (Table 2). - Complication rates were low across all BMI groups (Table 2). Conclusions: - Severely obese patients with BMI ≥40 experience higher risk of atrial arrhythmia following radiofrequency catheter ablation of paroxysmal atrial fibrillation compared with normal weight individuals. This corresponds with lower rates of first-pass isolation at higher BMI. - Patients across BMI categories experience similarly low rates of procedural complication.