Abstract 13378: Preclinical Assessment of the Feasibility of Thoracic Vein Isolation With Sub-Second Pulsed Field Ablation Using a Focal Lattice-Tip Catheter

Abstract

Introduction: Focal pulsed field ablation (PFA) using a 9mm lattice-tip ablation and mapping catheter (Sphere-9, Affera, Inc) can be used to deliver focal pulsed field ablation (PFA) at various atrial sites. We have previously shown that lattice-tip PFA using 3-5 sec deliveries creates efficacious atrial lesions. However, lattice-tip PFA still has a potential of shortening the ablation duration using tailored pulse designs. Accordingly, we assessed the feasibility and safety of thoracic vein (TV) isolation using ≤ 1 sec duration focal PFA in swine. Methods: A total of 4 swine underwent transfemoral venous access under general anesthesia. PF deliveries ≤ 1s were used to ablate a total of 8 TVs (4 pulmonary veins [PVs], 4 superior vena cava [SVC]) using lattice-tip catheter and its compatible PF generators (HexaPulse, Affera, Inc). TV potentials, venograms and phenic nerve injuries were assessed both acutely and after 24 hours; then, the animals were humanely sacrificed. Results: All 8 of 8 targeted veins (100%) were acutely isolated. Mean PFA application time for PVs and SVC was 13.1±4.1 and 12.8±1.0 sec, using 15.5±1.7 and 16.0±4.2 PFA applications, respectively. Persistent isolation was achieved in 7 of 8 (87.5%) TVs at 24 hrs. Gross necropsy demonstrated continuous and transmural lesions along the isolation line. The one SVC with reconnection demonstrated an obvious visual gap in the line. Microbubbles on the intracardiac echography were not seen during PFA applications, venography showed no reduction in vessel diameter, and the phrenic nerves were preserved in all swine. Conclusion: Significant shortening of pulse duration was not associated with compromise of acute lesion characteristics and TV isolation in a porcine model. But because of the potential discordance between preclinical and clinical outcomes, this strategy should be carefully tested in clinical studies.