Cryoablation of para-Hisian and mid-septal accessory pathways: long-term outcomes of a specific stepwise cryoablation protocol

Background: Although cryoablation (CA) of septally located accessory pathways (APs) is an established treatment for Wolff-Parkinson-White syndrome, its major limitation is the lack of data regarding long-term follow-up (FU). The present study sought to investigate long-term outcomes of a specific CA protocol targeting para-Hisian (P-H) and mid-septal (M-S) APs. Methods: 26 patients who previously underwent CA of PH or MS APs from 2004 to 2014, were prospectively considered to receive a follow-up (FU) during 2021. All subjects received an outpatient control visit, performing an exercise stress test and a 24-h ECG Holter monitoring. Results: Acute success was achieved in 22 patients (85%). One case of recurrence was reported at short-term FU. Long-term FU, performed after a mean time of 150 ± 37 months, did not show ventricular preexcitation recurrences, with a success rate of 81%, and without late adverse events. Symptoms reduction (12% vs. 96%, p<.001) and lower rates of antiarrhythmic drug use (12% vs. 62%, p<.001) were observed at long term-FU with respect to baseline. This clinical outcome was detected also among patients who underwent unsuccessful CA at baseline. Conclusions: Our CA protocol confirmed remarkable safety and efficacy throughout a longterm FU. Significant clinical improvement in terms of antiarrhythmic therapy discontinuation and symptoms reduction was also shown among patients who experienced acute failure of CA.