AB-452672-4 POINT-BY-POINT PULSED FIELD ABLATION USING A MULTIMODALITY GENERATOR: COMPARISON WITH RADIOFREQUENCY ABLATION IN REMAPPED CHRONIC SWINE HEARTS.

Abstract

In recent years, Pulsed Field Ablation (PFA) has emerged as a novel non thermal energy source for ablation. To compare lesion durability and collateral damage between unipolar/biphasic PFA and RF delivered through a contact-force sensing catheter both in a point-by-point fashion. A 4 arm pre-clinical study (n=12 swine) was designed with the multimodality generator TRUPULSE™ 2. PFA was delivered with nominal dose (12 pulses) in Group 1 whereas a high PFA dose (24 pulses) was used to evaluate energy safety in Group 2. RF arms served as controls with energy deployed through multimodality (Group 3) or market available (Group 4) generators. A contact-force catheter was used to focally deliver PFA/RF at the right superior pulmonary vein (RSPV), left atrial posterior wall (LAPW) and Roof, mitral isthmus (MI), cavotricuspid Isthmus (CTI), and RA posterior wall (RAPW). Average contact force was 12.7±3.7g. Animals were remapped at immediate post and 28 days post ablation. All animals were euthanized at 28 days and gross necropsy and histology followed. Acute RSPV isolation was achieved in all animals (Figure 1). At 28 days, remapping showed that RSPV isolation was maintained in all but one animal (Group 1) showing an electrical gap confirmed on histology. RAPW, CTI, MI (with exception of 2 animals, 1 in Group 2 and 1 in Group 3), and LAPW were maintained per histology as well. Differently from RF, both PFA arms had essentially similar histopathologic effect showing benign mature scar tissue repair with no necrosis nor inflammation (Figure 1). PFA applied to the RA lateral and posterior wall did elicit phrenic nerve response during ablation confirming ablations were done on the nerve. However, at 28 days remap, the nerve was stimulated and, in all animals, remained intact with no signs of damage on necropsy or histology. Representative samples were selected from the downstream/upstream organs including the brain, rete mirabile, heart, lungs, liver, esophagus, spleen, and kidneys, which showed no evidence of thrombo-embolic events. In swine models, point-by-point unipolar/biphasic PFA ablation showed durable PVI lesions acutely and at remapping without any sign of collateral damage after 28 days remap study. On histology, PFA lesions evolved with scar tissue without signs of necrosis nor inflammation. Further studies are needed to investigate the long-term safety and efficacy of this point-by-point PFA contact force sensing catheter.