Pulsed Field Ablation of Small Vessel-Related Arrhythmias: A New Catheter and Methods

Abstract Objectives Some arrhythmia targets are located in the epicardium or deep myocardium, which could be reached through the vascular approach. However, it is difficult to deliver ablation catheters to the distal vessels and their branches. In small vessels, the energy released is limited, and the risk of ablation is increased. The objective of this study was to design a linear catheter with pulsed field energy that is suitable for ablation in the distal vessels and to verify its efficacy and safety in canines. Methods A total of eight canines were randomly assigned to two observation groups: a 48-hour group (N=4) and a 30-day group (N=4). A 3 F 10-pole pulsed field ablation catheter was employed to ablate in the great cardiac vein, the middle cardiac vein, the anterior interventricular vein, and the distal small branches of the cardiac venous system. The characteristics of the ablation lesions were observed both grossly and microscopically. Results The surgical procedure was completed successfully. Pulsed field energy can travel through the fatty tissue to form a lesion in the cardiomyocytes. The mean depth of the lesion in the 30-day group (2.37±0.53 mm) was found to be reduced by 39% (P<0.001) in comparison to that observed in the 48-hour group (3.92±0.62 mm). Additionally, a transition zone of incomplete injury was discerned in the junction area of the 48-hour group. Canines exhibited no adverse effects intraoperatively nor postoperatively, and no appreciable damage was observed in the adjacent small arteries or the surrounding organs. Conclusion The pulsed field energy from small blood vessels can cause lasting, continuous lesions to the myocardium and is safe to use. The 3 F liner pulsed field ablation catheter has been proven to be efficacious and safe, with promising indications for future application.