PO-01-105 PRECLINICAL EVALUATION OF ACUTE AND CHRONIC CIRCUMFERENTIAL, LINEAR AND FOCAL PULSED FIELD ABLATION LESION SETS CREATED USING A “MAP & ABLATE” SPHERICAL MULTIELECTRODE ARRAY CATHETER

Abstract

A multielectrode spherical array catheter (Globe PF System, Kardium Inc., Canada) capable of both cardiac mapping and ablation with either pulsed field (PF) or radiofrequency (RF) energy has been developed. To assess efficacy and safety of creating flexible PFA lesion sets. Healthy canines (n=12) underwent transeptal access under general anesthesia. Electroanatomic maps with ostial tags, contact maps based on blood flow detection, and animated voltage maps were created. PFA was delivered at two strengths (1.7 & 1.8kV)and two pulse train designs (6 x 1.5-2 sec pulse-time or 3 x 3-4 sec pulse-time) to isolate a minimum of 2 pulmonary veins (PVs) (∼1 application) and to create linear/focal lesions. Animals survived in acute (n=6; 3±1 days survival) and chronic (n=12; 30±3 days survival) cohorts. In the chronic cohort, a repeat electrophysiological study was performed followed by detailed necropsy. In 12 animals, all targeted PVs (25/25, 100%) were acutely and durably isolated (13/13,100%). Discrete ablation on the roof and on the posterior wall was also successful in all 12 animals. Phrenic activation was only seen at one ablation site in one animal in each cohort. All 12 animals completed their survival period and gross pathological analysis revealed contiguous pink to dark-red lesions and pale-homogenous lesions in the acute and chronic cohorts, respectively. No thrombus or char was observed on the catheter. Histology revealed mean transmurality rates of 95.7% and 91% for the 74 and 75 sections analyzed in the acute and chronic cohorts, respectively. The lesion mean depths were 3.0±1.8 and 1.6±0.9 mm in the acute and chronic cohorts, respectively. There were variable amounts of hemorrhage and a minimal to moderate acute inflammatory response in the acute cohort. In the 2/6 canines that underwent necropsy on day 4 (the other 4 underwent necropsy on day 2 or 3), fibroblast proliferation was noted in addition to the above findings. In the chronic group, the entire lesion was replaced with fibrous connective tissue. No ablation damage to extracardiac structures was found. There were no signs of thromboembolism in any downstream organs, including no brain infarcts. This multielectrode spherical array catheter can deliver pulsed field ablation to both isolate PVs and deliver extra-PV left atrial lesions. These data provide the basis for ongoing and future clinical trials.