Dose-dependent ventricular lesion formation using a novel large-area pulsed field ablation catheter: A preclinical feasibility study

Abstract

Background: Pulsed field ablation (PFA) has shown promising data in terms of safety and procedural efficiency for pulmonary vein isolation. Large-area focal PFA catheter designs might be suitable to deliver deep and durable lesions in ventricular myocardium.

Objective: We aimed to investigate the dose-response of a novel large-area focal 3-dimensional (3D)-enabled map-and-ablate PFA catheter for ventricular ablation in a chronic preclinical swine model.

Methods: An 8F catheter with a 9-mm hexaspline tip was used for 3D mapping of both ventricles in a porcine model. Using a PFA generator 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 by intracardiac echocardiography and electrograms. The animals were kept alive for 1 week. Ablation lesions were assessed macroscopically after triphenyl tetrazolium chloride staining and by 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 (interquartile range [IQR], 4.1-5.6 mm) to 5.5 mm (IQR, 5.0-6.2 mm; P = .06) with bipolar ablation and from 4.9 mm (IQR, 4.4-5.2 mm) to 6.5 mm (IQR, 5.9-6.9 mm; P = .002) with monopolar ablation. On histologic evaluation, 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 PFA was able to create dose-dependent deep ventricular lesions durable 1 week after ablation.

Keywords: Bipolar PFA; Catheter ablation; Lesion depth; Map and ablate; Monopolar PFA; Pulsed field ablation; Ventricular ablation.