High power bipolar ablation of a thick myocardium: ex-vivo study using externally-irrigated large-tip ablation catheters

• Published in: Europace (London, England) England), 2022-05, Vol.24 (Supplement_1)
• Main Authors: Futyma, P, Zarebski, L, Burbelka, A, Pawlik, A, Futyma, M
• Format: Article
• Language: English
• ISSN: 1099-5129; 1532-2092
• DOI: 10.1093/europace/euac053.379

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Bipolar radiofrequency catheter ablation (Bi-RFCA) can overcome some challenges related with treatment of intramural ventricular arrhythmias. However, there’s no data if Bi-RFCA can be effective in the setting of a thick myocardium. Aim To estimate safety and efficacy of high-power long-duration Bi-RFCA in the setting of a thick myocardium and to demonstrate feasibility of external irrigation for large-tip ablation catheters (AC). Methods The study was performed in a saline bath containing a fresh bovine heart. Bi-RFCA of the left ventricular (LV) and right free wall, interventricular septum, papillary muscle and LV summit at power settings of 70W was performed using two solid-tip 8mm AC in a parallel orientation. Irrigation using normal saline of each AC was provided from a long sheath advanced to the level of 2nd (distal irrigation – DI) or 3rd (proximal irrigation – PI) AC electrode. Post-Bi-RFCA lesions were evaluated macroscopically. Results Mean intercatheter distance was 28±11 mm, range 12-50 mm and a total number of 12 high-power Bi-RFCA lesions were performed. Mean Bi-RFCA time was 108±42s. Complete transmurality was achieved in 4 (33%) of lesions (mean 17±3 mm thickness, range 12-20 mm) whereas borderline transmurality was observed in further 2 (17%) lesions (mean 23±0,5 mm thickness, range 22-23 mm). No transmurality was present in the remaining 6 (50%) lesions (mean 38±7 mm thickness, range 30-50 mm). Steam pops occurred in 25% of Bi-RFCA applications. Temperature drop during external irrigation was significantly higher in the DG group vs PG 15°C vs 7°C, p=0,0046). Conclusions Bi-RFCA of a myocardial thickness above >30mm is challenging. High-power (70W) long-duration Bi-RFCA is associated with substantial incidence of steam pops. Further histopathological studies should evaluate levels of transmurality using high power Bi-RFCA at muscle thickness between 20-30mm. External irrigation of solid-tip large AC is feasible and can significantly reduce AC tip temperature. 70W bipolar ablation in a thick tissue