Bipolar endo-epicardial RF ablation: Animal feasibility study

Paweł Derejko; Izabela Janus; Piotr Kułakowski; Jacek Kuśnierz; Jakub Baran; Urszula Hangiel; Joanna Proszek; Piotr Frydrychowski; Marcin Michałek; Agnieszka Noszczyk-Nowak

doi:10.1016/j.hrthm.2024.02.009

Bipolar endo-epicardial RF ablation: Animal feasibility study

Heart Rhythm. 2024 Feb 8:S1547-5271(24)00126-7. doi: 10.1016/j.hrthm.2024.02.009. Online ahead of print.

Affiliations

¹ Department of Cardiology, Medicover Hospital, Warsaw, Poland; Department of Cardiac Arrhythmias, National Institute of Cardiology, Warsaw, Poland. Electronic address: pderejko@yahoo.com.
² Faculty of Veterinary Medicine, University of Environmental and Life Sciences, Wroclaw, Poland.
³ Department of Cardiology, Centre for Postgraduate Medical Education, Grochowski Hospital, Warsaw, Poland.
⁴ Department of Cardiology, Medicover Hospital, Warsaw, Poland.
⁵ Biosense Webster, Warsaw, Poland.

PMID: 38336196
DOI: 10.1016/j.hrthm.2024.02.009

Abstract

Background: Bipolar radiofrequency ablation (B-RFA) is a method used to treat the arrhythmia substrate resistant to unipolar ablation. Few studies have addressed endo-epicardial B-RFA.

Objective: The aim of the study was to evaluate chronic lesions resulting from endo-epicardial B-RFA and to determine optimal settings for such procedures in an animal model.

Methods: In 7 pigs, up to 5 radiofrequency applications per animal were performed with 2 electrodes placed on both sides of the left ventricular free wall. Current was delivered for 60 seconds by a generator dedicated for B-RFA with power settings of 25, 30, 35, 40, and 50 W.

Results: At 12 weeks after ablation, 31 lesions were assessed. Their maximal cross-sectional area ranged from 7.2 to 68 mm² and correlated with total power delivered (r = 0.53), with temperature increment at the endocardial catheter (r = 0.65), and inversely with temperature decrement at the epicardial catheter (r = 0.54). For power values between 30 and 40 W, the lesion area did not differ significantly (P = .92). Lesion depth ranged from 1.9 to 11 mm and correlated with impedance decrement (r = 0.5). Lesions were transmural in 8 cases. Lesion depth/wall thickness ratio was on average 0.6 ± 0.3, with the smallest value for 25 W (0.5 ± 0.3) and the largest for 50 W (0.8 ± 0.3). Steam pops occurred at a power range of 30-50 W, with an incidence of 1 in 5 applications, with 1 case of fatal tamponade at 40 W. Impedance decrement, endocardial catheter temperature increment, and endocardial electrogram amplitude decrement were greater during applications with steam pops.

Conclusion: Chronic lesions resulting from endo-epicardial B-RFA appear smaller and less often transmural compared with acute lesions described in the literature. The incidence of steam pops during endo-epicardial B-RFA is relatively high even at low powers.

Keywords: 3D mapping; Bipolar ablation; Epicardial ablation; Epicardial access; Lesion dimensions; RF ablation; Steam pop.