Dose-Dependent Ventricular Lesion Formation Using a Novel Large-Area Pulsed Field Ablation Catheter: A Preclinical Feasibility Study.

Background Pulsed-field ablation (PFA) has shown promising data in terms of safety and procedural efficiency for pulmonary vein isolation (PVI). Large-area focal PFA catheter designs might be suitable to deliver deep and durable lesions in ventricular myocardium. Objective To investigate the dose-response of a novel large-area focal 3D-enabled map-and-ablate PFA catheter for ventricular ablation in a chronic preclinical swine model. Methods A 8 F catheter with a 9 mm hexaspline tip was used for 3D mapping of both ventricles in a porcine model. Using a PFA generator (FARASTAR, Boston Scientific), with a proprietary waveform optimized for the catheter, left- and right-ventricular lesions were placed with either a monopolar or bipolar ablation vector, and with 1,2,or 4 applications per site (2.0 kV/application). Tissue contact was ensured using intracardiac echography and EGMs. The animals were survived for 1 week. Ablation lesions were assessed macroscopically after triphenyl tetrazolium chloride staining and using histopathology. Results A total of 69 chronic ventricular lesions from 7 pigs were available for analysis. By stacking 4 PFA applications rather than a single application, median chronic lesion depth increased from 4.8 mm (IQR 4.1-5.6) to 5.5 mm (IQR 5.0-6.2), p=0.06 with bipolar ablation, and from 4.9 mm (IQR 4.4-5.2) to 6.5 mm (IQR 5.9-6.9), p=0.002 with monopolar ablation. On histology, lesion borders were clearly demarcated, with vessels and nerves preserved. Conclusion A novel large-area focal ablation catheter with the ability for 3D-mapping and pulsed-field ablation was able to create dose-dependent deep ventricular lesions durable 1 week after ablation.