Monopolar biphasic focal pulsed field ablation directly at the atrioventricular junction and from within the non-coronary cusp: The PFA-CONDUCT study

Background The efficacy and safety of monopolar biphasic focal pulsed field ablation (F-PFA) in close proximity to the atrioventricular (AV) node remain unknown. Objective To describe the effect of direct or indirect F-PFA application at the AV junction. Methods In pigs, F-PFA (Centauri) was applied directly at the AV junction (n=3) and indirectly from within the aortic non-coronary cusp (NCC) (n=5), followed by macroscopic gross and histological analysis. In five patients planned for a pace-and-ablate strategy, F-PFA was applied at the AV junction. In one patient with recurrent parahisian atrial tachycardia (AT) and previously failed ablation, F-PFA was applied from within the NCC. Results In pigs, direct F-PFA applications at the AV junction were associated with junctional beats and resulted in complete AV block after 2-3 F-PFA applications. Tissue histology revealed a lesion depth of approximately 8mm with minor haemorrhage and leukocyte infiltration. F-PFA from within the NCC resulted in a transient increase in the AV node’s Wenckebach cycle length and one pig had transient AV block, which recovered within 10 min. In five patients undergoing pace-and-ablate strategy, F-PFA applications at the AV junction resulted in sustained AV block. In one patient, application of F-PFA from within the NCC resulted in termination and non-inducibility of a recurrent incessant parahisian AT without AV block. There were no immediate or long-term complications. Conclusion F-PFA directly at the AV junction results in non-reversible AV block. F-PFA from within the NCC may represent a promising strategy for treating parahisian arrhythmias while preserving AV conduction.