PO-04-092 SAFETY AND EFFICACY OF DIFFERENT FIELD STRENGTHS OF PULSED-FIELD ABLATION IN ACHIEVING DURABLE CAVOTRICUSPID ISTHMUS BLOCK: A PRECLINICAL STUDY

Abstract

Pulsed-field ablation (PFA) is an emerging modality for pulmonary vein isolation. There is limited data on the effect of different field strengths of PFA in achieving durable cavotricuspid isthmus block. This study examines the safety and efficacy of three different field strengths of PFA in achieving durable CTI block. In this study, eleven healthy swine (mean weight= 36.6 ± 3.8 kg) underwent a CTI ablation and followed up for a minimum of 12 weeks. An 8-French, 6-electrode purpose-designed steerable linear catheter, and an integrated PFA system were used to deliver biphasic bipolar PFA of three different field strengths and a predefined number of applications. The CTI ablation was performed using low, intermediate, and high field strengths of PFA, 1800 (n=4), 2300 (n=3), and 2800 Volts (n=4), respectively. PFA was applied 6, 8, or 11 times for each CTI line using low, intermediate, and high PFA field strengths. A three-dimensional electro-anatomical map (3D-EAM) was obtained at baseline, and three months after index ablation. Acute bidirectional CTI conduction block was achieved at 100% of the animals with a mean of 8.7 ± 2.1 applications per line. Repeated 3D-EAM at 12 weeks showed a persistent bidirectional CTI block in 10 of 11 animals (91%). There was only one CTI reconnection demonstrated at follow-up with voltage mapping. This was previously ablated with the lowest PFA dose (6 applications of 1,800V). No PFA-related complication was observed in the animals during the peri- and post-procedural periods. This study demonstrated the safety and efficacy of PFA in CTI ablation. The higher field strength of PFA was associated with a durable bidirectional CTI block. The lower PFA field strength with the higher number of applications was associated with the durable lesion sets. A lower PFA field strength with fewer applications resulted in acute reversible electroporation.