Comparison of vagal effect during pulmonary vein isolation with radiofrequency and Pulse field ablation: a retrospective study

Abstract Background Vagal responses are commonly observed during pulmonary vein isolation (PVI) for atrial fibrillation (AF) ablation with both pulsed-field ablation (PFA) and radiofrequency (RF) approaches. Objective To compare the effects of PFA and RF on the autonomic nervous system during PVI. Methods This monocentric, retrospective observational study included consecutive patients scheduled for AF ablation with a variable loop PFA catheter from March to September 2024. A control group, matched by age, sex, and CHA2DS2-VASc score, was treated with RF ablation. Vagal reactions were noted if patients experienced pauses >3 seconds or bradycardia <40 bpm during ablation. Heart rate and heart rate variability were assessed pre- and post-ablation. Results A total of 39 patients were included in each group, with similar baseline demographics and AF characteristics. Acute electrical isolation was achieved in 100% of pulmonary veins (n = 312) across the 78 patients. Vagal reactions were significantly more frequent in the PFA group (41% vs. 5.1%; p<0.001). In the PFA group, vagal reactions occurred in both left-sided (11/16) and right-sided (6/16) veins, while no vagal reactions were observed in the right-sided veins of the RF group (p=0.11). Heart rate and heart rate variability pre- and post-ablation were similar between the groups. Conclusion PFA induces frequent vagal responses during PVI for paroxysmal AF, but does not appear to cause persistent alterations in autonomic nervous system function.