Vagal response in pulsed field ablation: comparison between lattice-tip monopolar and pentaspline bipolar catheter

Background Pulsed field ablation (PFA) for pulmonary vein (PV) isolation can elicit transient vagal responses (VR) during energy delivery. These intraprocedural responses are brief and resolve within seconds. Purpose To compare the incidence and anatomical distribution of VR during PFA performed with a lattice-tip monopolar catheter and a pentaspline bipolar catheter. Methods We analyzed prospectively collected data on consecutive patients with paroxysmal atrial fibrillation undergoing first ablation procedure between February 2024 and October 2025. Patients receiving PV isolation using either the pentaspline bipolar or the lattice-tip focal monopolar catheter were included in the study. Patients receiving prophylactic glycopyrrolate and atropine or with cardiac implantable electronic devices were excluded. Clinically relevant VR was defined as sinus bradycardia, asystole, or atrioventricular block immediately after a PFA application. Location of the site of VR was annotated. Results VR was observed in 274 patients, occurring in 159 patients (58.0%) treated with the pentaspline catheter and in 115 patients (41.9%) treated with the lattice-tip catheter. In the left superior PV, VR occurred in 125 patients (78.6%) with the pentaspline catheter and in 27 (23.5%) with the lattice-tip (p<0.001). In the right superior PV, no VR was observed with the pentaspline catheter, whereas 75 events (65.2%) occurred with the lattice-tip (p<0.001). In the medial portion of the low posterior wall (corresponding to the posteromedial left ganglionated plexus), VR was observed in 34 patients (21.4%) with the pentaspline catheter and in 13 (11.3%) with the lattice-tip catheter (p=0.043). Conclusion Despite comparable overall rates of vagal response, the anatomical sites of VR occurrence differed depending on the PFA system.