Single or multiple pulsed field applications: Intracardiac electrogram changes and implications for procedural end points

Background Pulsed field ablation (PFA) using a pentaspline catheter is increasingly applied for pulmonary vein (PV) isolation, but standardized methods to assess durable lesion formation are lacking. Objective We aimed to investigate the impact of incremental PFA applications on electrogram (EGM) characteristics and determine whether EGM signatures serve as markers for effective lesions. Methods PV EGMs of a cohort of consecutive patients were analyzed before and after single, double, and quadruple PFA applications. Bipolar voltage amplitude (BVA) and signal power in different frequency bands (>50 Hz, >75 Hz, and >125 Hz [HF125]) were quantified. EGMs were reassessed after 60 seconds, and pacing was performed to evaluate PV pace capture. Results This analysis included 4230 EGMs of 83 patients. Immediately after ablation, no differences in BVA and frequency power were observed between groups. After 60 seconds, significant differences were present for all features in the single, double, and quadruple groups: BVA (0.27 mV vs 0.26 mV vs 0.13 mV), >50 Hz (39 μV2 vs 35 μV2 vs 8 μV2), >75 Hz (10 μV2 vs 13 μV2 vs 3 μV2), and HF125 (3 μV2 vs 2 μV2 vs 1 μV2). EGM features recovered within 60 seconds in the single and double groups but not in the quadruple group. Pace capture at 5 V was best predicted by an HF125 threshold of 2.5 μV2 and a BVA threshold of 0.28 mV. Conclusion Only quadruple PFA applications ensured persistent lesion effects over the observation period. A combined end point using an HF125 cutoff of 2.5 μV2 and BVA cutoff of 0.28 mV may provide accurate confirmation of PV isolation with the pentaspline catheter.