Background: Pulmonary vein isolation (PVI) is the cornerstone of every interventional treatment for patients with atrial fibrillation (AF). Recently, the novel high power short duration (HPSD) protocol for RF AF ablation showed sufficient efficacy and safety data. This study aims to investigate the short and long-term success in obese and very obese patients.

Methods: Consecutive patients undergoing AF ablation with HPSD (50W; ablation index-guided; target AI 350 for posterior wall ablation, AI 450 for anterior wall ablation) using the ThermoCool SmartTouch SF DF catheter were included. Patients were divided into 4 groups (BMI 18.5 – 24.9 ≙ normal weight; BMI 25 – 29.9 ≙ overweight; BMI 30 – 39.9 ≙ obese; BMI >40 ≙ morbidly obese). Periprocedural parameters and complications were recorded and analyzed. Short-term endpoints included intraprocedural reconnection of at least one PV after initial isolation and intrahospital AF recurrence; midterm endpoint AF freedom after 3 months, long-term endpoint AF freedom after 12 months.

Results: A total of 815 patients underwent AF ablation with HPSD (67  10 years; 57% male; 42% paroxysmal AF; 34% redos). 175 patients were normal weight (21%), 325 overweight (40%), 273 obese (34%) and 42 morbidly obese (5%). Only morbidly obese patients revealed higher procedure time, fluoroscopy time and ablation time compared to normal weight (all p<0.05). Groin complications occurred more often among morbidly obese than in normal weight patients (p=0.023), whereas thermal esophageal lesions were more frequent among normal weight patients (p=0.015). Short-term success including intraprocedural reconnection and AF recurrence during 6 weeks blanking period was equal among all groups, except for morbidly obese patients (both p<0.05). Recurrence of AF after 12 months was not different among all groups (62% vs. 62% vs. 68% vs. 57%; p=0.539), irrespective of first PVI or redo procedure. In multivariable regression analysis female gender and LA size, but not obesity were associated with increased AF recurrences.

Conclusions: Despite slightly increased complication rates and impaired short-term success in morbidly obese patients, HPSD AF ablation is safe and feasible in overweight, obese and morbidly obese patients. HPSD AF ablation technique should be the technology of choice especially for obese patients due to short RF times.