Lesion Morphometry of the Pentaspline Pulsed Field Ablation Catheter: Understanding Catheter Pose, Rotation, and Dosing.

Background: The pentaspline pulsed field ablation catheter achieves pulmonary vein isolation using 8 stacked, pose-specific applications with rotation. The morphology of pose-specific, single or double applications has not been described.

Methods: One or 2 applications were delivered to select veins and discrete atrial and ventricular sites in 9 swine. General anesthesia with neuromuscular paralysis ensured a stable position. Preablation, postablation, and serial intraprocedural mappings were performed to characterize electrical vein isolation and dynamic voltage changes. Upon euthanize at 2 days (7 of 9 swine), hearts were subject to pathological examination.

Results: Six superior vena cavae received single or double applications in basket pose without rotation. Despite incomplete dosing, acute electrical isolation occurred in 4 of 6 veins. None recovered conduction over 40 minutes, but all 3 isolated veins that were remapped at 2 days had reconnected. Lesions were linear (15-16 mm) with gaps and significantly wider with double versus single applications (8.2±2.8 versus 6.1±2.0 mm; P=0.02). Similar lesions, with acute isolation and subsequent reconnection, were observed in 3 of 4 ablated pulmonary veins. Double flower pose applications to the posterior atrium created wide (≈40×30 mm) confluent lesions, whereas single applications resulted in curvilinear lesions with variable gaps. Flower pose lesions (single or double) in the right ventricle were flower-shaped, linear with gaps, and with depths up to ≈5 mm.

Conclusions: The pentaspline catheter in the basket pose creates perivenous linear lesions with gaps. Single applications in flower pose generate narrow linear lesions with variable gaps, whereas double applications result in wide, confluent lesions.