PO-03-034 OUTCOMES OF A 3-MONTH MAPPING STUDY FOLLOWING PULMONARY VEIN ISOLATION USING A NOVEL SINGLE-SHOT PULSED FIELD ABLATION SYSTEM IN A PORCINE MODEL

Abstract

Pulsed field ablation (PFA) is a non-thermal ablative strategy that achieves cell death via electroporation. We investigated the durability of PFA lesions using 2 novel PFA/mapping catheters (CRC EP Inc, San Jose, CA) at repeat EP studies performed 3 months post-ablation. In total, 16 pulsed field applications were delivered using the PFA catheters in 3 swine under general anesthesia in the absence of paralytic agents, including: 1 application to the left atrial appendage, 9 applications to the right pulmonary veins (PVs), 3 applications to the inferior common PV and 3 applications to the right ventricle (RV). The design of the PFA catheters consists of an 8-Fr, 16-electrode, bidirectional, 25-mm or 30-mm spiral, the latter bearing 2 distal pairs of mapping electrodes active even during PFA delivery. The catheters were inserted through a commercially available 8.5-Fr steerable introducer (Agilis, Abbott, Chicago, IL). Bipolar PFA (>2 kV) was performed using single-shot, QRS-gated applications under 3D mapping and intracardiac echocardiographic guidance. Skeletal muscle activation intensity was quantified using an accelerometer (Phyphox, Aachen, Germany). Lesions were assessed by pre- versus post-EGM analysis, pacing threshold, 3D voltage mapping (EnSite, Abbott), necropsy, and histology. All applications were single-shot (34 ± 12 s) without repositioning the catheter. Minimal microbubbling was observed with mild to no skeletal muscle stimulation (acceleration <4 m/s2). No tachyarrhythmias were induced during PFA. Immediately post-ablation, bilateral PV isolation was confirmed with partial ablation of posterior wall and the coronary sinus (CS). Repeat 3D mapping at 3 months validated complete lesion durability at the PFA locations, once again illustrating bilateral PV isolation. However, there was conduction recovery at the adjacent, non-ablated/non-targeted sites (e.g., the posterior wall and CS). Accordingly, there was significant reduction in 3-month post- versus pre-PFA EGMs at the atrial PFA sites (1.38 ± 0.70 mV vs. 0.04 ± 0.03 mV, P<0.0001) and at the RV ablation sites (1.6 ± 1.3 mV vs. 0.2 ± 0.1 mV, P<0.05) with marked increase in the pacing thresholds (>20 mA vs. <10 mA, P<0.001). Lesions were contiguous measuring 26 ± 8 x 18 ± 6 mm and transmural in the atria and 38 ± 14 mm x 28 ± 9 mm and 5 ± 2 mm deep in the RV. A novel PFA catheter system can create large, single-shot atrial and ventricular lesions in vivo that are completely durable at 3 months.