Endocardial Atrial Lesion Characteristics With Pentaspline Pulsed Field Ablation: Insights From Serial Mapping in Patients

Background: Pentaspline ablation (31 mm, Farapulse) catheter lesions can differ by pose, repetition, and contact, thus affecting morphology. Objective: Lesion morphology may offer insights into suboptimal ablation durability and can help optimize ablation strategies. Methods: In 25 patients, 1–2 applications were delivered to pulmonary veins (PV, n = 16), posterior left atrium (LA, n = 6) and LA roof (n = 3). Pre, 1- and 5-min postablation maps were created. Isolation area was identified by < 0.15 mV. Three patients after cavotricuspid isthmus (CTI) ablation were mapped. Results: Despite only 1 or 2 basket pose applications without rotation, all 16/16 PVs (100%) were acutely isolated. Only 3/16 PVs (12.5%) reconnected by 5 min revealing asymmetric, band-like perivenous lesions. Posterior LA flower applications were irregular, with the smallest mean dimensions of 14.9 and 17.7 mm. Isolation area regressed acutely, more so for single but also for double applications. However, regression occurred only for PV (6.7 ± 6.0 vs. 1.3 ± 1.5 cm²) and not for posterior wall lesions (2.9 [1.9–3.6] vs. 2 [1.65–2.4] cm²). Double roof applications resulted in circular, doughnut-shaped, or even minimal lesions. Flower pose CTI lesions had median widths of 43.1, 21.3, and 24.9 mm along the line. Conclusion: Acute PV isolation always occurs despite minimal dose delivery and is unreliable for lesions assessment. Even double applications have relevant regression, and this occurs more so in PV than LA posterior wall. Despite 2 applications, posterior LA lesions were smaller than the catheter diameter and roof lesions footprints can vary widely. Dose related footprint assessments are needed to help optimize ablation and durability.