B-po04-019 subchronic versus chronic safety assessment of a circular irreversible electroporation catheter design and a pulse field ablation generator

Pulsed field ablation (PFA) is a uniquely tissue-selective, nonthermal cardiac ablation modality. To understand the progression and immediate impacts of PFA, this study evaluated the subchronic (7±3 day) and chronic (30±3 day) safety and performance of a novel PFA system when simulating PV and SVC isolation in a porcine beating heart model. A total of 10 swine were divided between the subchronic, (n=6), and chronic cohorts (n=4). The PFA Ablation System consisted of the Multi-Channel IRE Generator System and a Multi-electrode Circular IRE Catheter. Lesions were performed into the right and left atrium to perform RSPV and SVC isolations, in addition to creating stacked lesions in the LA roof and RA posterior wall. Acute PV and SVC isolation was achieved in 10/10 swine (100%) and demonstrated 100% durability in both the sub-chronic and chronic cohorts. Durable scarring was also observed on the LA roof and RA posterior wall. Histology demonstrated that all the cardiac sites ablated showed discrete zones of loss of myocardial fibers and/or smooth muscle cells with preservation of the tissue architecture with resultant fibrocellular replacement, neovascularization, and neocollagen deposition. There were no treatment-related changes in other tissues, including complete sparing of the phrenic nerve. Pulse field ablation for PV and SVC isolation was feasible, safe and demonstrated a myocardial-specific ablative effect. Lesions made at the PV, SVC, LA roof and RA posterior wall all demonstrated durability. Comparison of a subchronic and chronic subgroups demonstrates that clear signatures of PFA lesion formation can be seen as early as 9 days post ablation.