Pulsed field ablation versus Cryo-PVI in obese patients

Background
Pulmonary vein isolation (PVI) is a highly effective therapy for treating atrial fibrillation (AF). PVI using non-thermal pulsed field ablation (PFA) has recently shown comparable outcomes to thermal ablation such as cryoballoon ablation (CBA). Single-shot devices such as CBA and by extension PFA offer several advantages, particularly in reducing ablation time, potentially benefitting patients with comorbidities. Despite increasing prevalence of obesity, there is limited data on the optimal PVI method for this patient population.

Aim
The aim of this study was to compare procedural data, outcome and complication rates of PFA to CBA in obese patients.

Methods
All de novo PVIs performed at our center between September 2021 and June 2023 using PFA and CBA were analysed. Only obese patients (BMI ≥ 30 kg/m²) undergoing de novo PVI were included in this analysis.

Results
A total of 85 PVI procedures were included. 32 (37.6%) patients underwent PFA and 53 (62.4%) patients received CBA. Baseline characteristics were comparable between groups. In the PFA group (65.6% male; mean age 67.7 ± 8.0 years), 68.8% of patients suffered from persistent AF, with an average BMI of 33.3 ± 3.0 kg/m². In the CBA group (73.6% male; mean age 64.3 ± 10.3 years), 47.2% of patients suffered from persistent AF, and the average BMI was 33.0 ± 2.9 kg/m². Procedure time was significantly shorter with PFA compared to CBA (PFA: 57.0 ± 19.7 min; CBA: 64.7 ± 17.3 min; p = 0.0167), and the use of contrast medium was significantly lower in the PFA group (PFA: 10.9 ± 8.7 ml; CBA: 47.2 ± 23.0 ml; p < 0.0001), while fluoroscopy time (PFA: 12.2 ± 4.2 min; CBA: 11.2 ± 4.2 min, p = 0.2) and dose (PFA: 6872.8 ± 11072.8 mGy·cm2; CBA: 7834.5 ± 13419.2 mGy·cm2; p = 0.6) were comparable. Major complications in the PFA group were one pericardial tamponade, and two intermittent sinus arrests. In the CBA group one patient experienced a pseudoaneurysm and one patient developed pneumonia due to aspiration (PFA: n=3, 9.4%; cryo: n=2; 3.8%; p = 0.3). After a mean follow-up of 310.2 days, 83.3% of patients in the PFA group and 77.4% in the CBA group were free from atrial arrhythmia, with no significant difference in the survival analysis (p = 0.6, log-rank HR 0.75, 95% CI 0.28–2.04).

Conclusion
In obese patients, PFA is comparably safe and effective to achieve complete PVI with the potentially added benefit of a shorter procedure time and reduced contrast medium usage compared to CBA. However, this study primarily included patients with class one obesity and only few with higher-grade obesity. Risks associated with ablation may increase in patients with higher grade of obesity and PFA might be even more beneficial for these patients. 



Figure 1: Kaplan-Meier analysis