Evaluation of effectiveness and outcomes of pulsed field ablation of atrial fibrillation in patients with obesity

Background Pulsed field ablation (PFA) with the pentaspline catheter is a non-thermal technology for pulmonary vein isolation (PVI) of atrial fibrillation (AF). Obesity and the associated comorbidities are known to be a risk factor for AF. However, ablation in this patient cohort remains challenging due to difficult sedation, patient movement, difficult airways management and enlarged atria. Purpose The objective of this study is to evaluate the influence of high body mass index (BMI) on procedural characteristics, safety, acute efficacy, and long-term outcomes of PVI using the pentaspline PFA catheter. Methods Consecutive patients with symptomatic paroxysmal or persistent AF who underwent PFA-PVI between May 2021 and April 2024 were retrospectively categorized into two groups with normal weight patients in G1 (BMI ≤ 24.9) and severely obese patients in G2 (BMI ≥35 kg/m2). Results A total of 431 patients were enrolled (G1: 328 patients; G2: 103 patients). Patients in G2 were younger (G1: 68.7±11.9; G2: 62.4±9.6; p<0.001) and prevalence of hypertension (G1: 46.3%; G2: 83.5%; p <0.001), diabetes (G1: 3.7%; G2 :25.2%; p<0.001) and persistent AF (G: 35.1%; G2: 56.3%; p <0,001) was higher in G2. Left atrial diameter (G1: 39.3 ± 7 G2: 46.4 ± 8; p< 0.001) was also larger. All pulmonary veins were successfully isolated using solely PFA. Total procedure time was higher in G2 (G1: 31.5 ± 10.3; G2: 35.1± 12.6; p=0.011). While there was no significant difference in fluoroscopy time (G1: 7 ± 5.1; G2: 7.7 ± 5.6; p=0.211), overall fluoroscopy dose was significantly higher in G2 (G1: 193 ± 171; G2: 825 ± 698; p< 0.001). In total there were 10 complications, with no difference between the groups (G1: 2.4%; G2:1.9%; p=0.770), with most complications related to the access site (4/10). Recurrence of AF in blanking time was observed in 17.7% of patients and no difference between groups was observed (G1: 18.6%; G2: 14.7%; p=0.368). The 1-year freedom from AF in paroxysmal AF was significantly worse in G2 (G1: 84.7%; G2: 59.1%; p<0.001) whereas in persistent AF no significant difference in 1-year freedom from AF was found (G1: 57.9%, G2:62.9%; p= 0.664). A total of 49 repeated procedures were performed (G1: 37; G2: 12) and significantly more durably isolated veins were found in G1 (127/148; 85%) compared to G2 (35/48; 72%; p=0.040). Conclusion PFA proved highly effective in both groups with a good safety profile. However, severely obese patients with paroxysmal AF showed a reduced 1-year success rate. Interestingly, the rate of durably isolated PVs was lower in severely obese patients which may have contributed to the higher recurrence rate of paroxysmal AF patients. Strategies to improve PVI durability in these patients should be evaluated in future. In conjunction with life style modification, PFA may represent a strategy to enhance rhythm control in the context of severe obesity.1-year follow up paroxysmal AF 1-year follow up persistent AF