PO-711-02 POST- ABLATION UNIPOLAR ELECTROGRAM CHANGES: A PRECLINICAL EVALUATION COMPARING RADIOFREQUENCY VS PULSED FIELD ABLATION USING A “MAP AND ABLATE” MULTIELECTRODE ARRAY CATHETER

Abstract

A multielectrode spherical array catheter (Globe, Kardium Inc, Canada) capable of mapping and ablation with either radiofrequency (RF) and pulsed field (PF) energy has been developed. To compare acute unipolar electrogram changes in atrial tissue after RF vs PF ablation. Healthy canines underwent transseptal access under general anesthesia, followed by circumferential pulmonary vein isolation, as well as linear and focal ablation as part of an efficacy and safety evaluation. Temperature controlled RF ablation (63ºC for 3 min) or PF using 1.6-2 kV/application (either gated or ungated modes) were used in separate animal cohorts. Only animals where focal/linear ablations were placed on the left atrial roof were selected so as to compare electrogram features at identical anatomic sites in both cohorts. We compared pre-ablation with post-ablation unipolar electrograms (1-225 Hz) recorded at i) the electrodes selected for ablation (Row 1), ii) from immediately adjacent electrode rows (Row 2, 3.5-6mm away), and iii) from electrodes 2 rows away (Row 3, 7-12 mm away; Figure). A total of 21 ablated sites (Row 1) and 27 adjacent Rows (2 & 3) were analyzed in the RFA group; similarly 77 and 81 sites were analyzed in the PFA group. Lesion transmurality was seen across the focal lesions on the left atrial roof for both the RF and PF applications. With both RF and PF ablation, there was complete loss of the negative deflection of the unipolar electrogram, as well as diminution of the R wave accompanied by a current of injury in Row 1. In the RF cohort, Row 2 demonstrated minimal loss of the negative deflection with mild injury current. However, PF ablation resulted in significantly greater loss of the negative deflection and current of injury was observed in Row 2, compared to RF ablation. Furthermore, in the PF group, even Row 3 demonstrated some degree of loss of negative deflection and injury current, whereas in the RF group this row was completely preserved. Loss of negative deflection of the unipolar electrogram, a feature that suggests transmural ablation in the setting of RF ablation is also seen with PF . However, the extent of unipolar changes extend further (7-12 mm) from the site of ablation with PF compared to RF, where these changes were milder and restricted to 3.5-6 mm.View Large Image Figure ViewerDownload Hi-res image Download (PPT)