Transcatheter cryo-ablation of septal accessory pathways, multicenter observational study in Japan

Background: Ablation using radiofrequency energy has to be carefully performed when the arrhythmia substrate is located in close proximity to the atrioventricular (AV) node due to the risk of inadvertent permanent AV block. The aim of this study was to evaluate the efficacy and safety of catheter-based cryo-therapy for septal accessory pathways (APs).

Methods: A total of eleven patients (median = 56.3 years, range 13-74 years) with septal APs underwent cryoablation. Ice-mapping was performed during sinus rhythm and an AV reciprocating tachycardia utilizing the APs as a requisite limb with cooling of the catheter tip temperature to a maximum of -30℃ for less than 45 s. Cryo-ablation was performed for 4 min at a temperature of -80℃ only if ice-mapping abolished the pre-excitation or retrograde conduction over the AP without injury to the AV nodal conduction.

Results: Cryo-ablation was acutely successful in all eleven patients. No permanent cryo-related complications or adverse outcomes were reported. During the follow-up (range 14-26 months), no patients experienced any arrhythmia recurrences.

Conclusion: Ice-mapping was a feasible and reliable method to determine the exact location of the APs owing to the possibility of validating the ablation site. Cryo-ablation of APs located near the AV junction is a safe and efficacious technique with a high success rate over the long term.

Irb information: Ethical Committee of Japan Red Cross Yokohama City Bay Hospital #2018-19.