Detection of Accessory Pathway Recurrence at Standard and Abbreviated Waiting Periods and Implications for Recurrence Following Pediatric Radiofrequency Ablation

INTRODUCTION: Despite routine use, the benefit of a post-ablation waiting period (WP) following pediatric radiofrequency (RF) accessory pathway (AP) ablation remains unclear. The incidence of WP recurrence, the optimal WP duration, and the impact of the WP on subsequent recurrence are not well defined. METHODS: We performed a retrospective study of pediatric patients who underwent acutely successful RF AP ablation from September 2020 to February 2025. Patients with prior ablation, multiple pathways, cryoablation, or additional arrhythmia mechanisms were excluded. A total of 232 patients were included. All underwent 30 min post-ablation WP testing and were monitored for 24 h recurrence on a Holter monitor. Recurrence during follow-up was also assessed. A subset of 104 patients underwent 10 min WP testing in addition to 30 min WP testing. A cumulative procedural risk score (contact issue, difficult pathway characteristics, mechanical trauma, and return of AP conduction after transient effect) was compared between recurrent and non-recurrent pathways, both for WP and follow-up recurrence. Bivariate comparisons and logistic regression were performed. RESULTS: Among 232 patients (median age 13.0 years), 30 min WP recurrence occurred in 8 patients (3.4%), all with manifest pathways. Detection of WP recurrence resulted in absolute risk reductions (ARR) of 4.3% and 3.0% in 24 h and follow-up recurrence, respectively, among manifest pathways. A 2.2% ARR in follow-up recurrence was observed in the total cohort including concealed pathways. WP recurrence was associated with increased risk of follow-up recurrence (OR 7.3, 95% CI 1.6-33.2, p = 0.01). Among the 104 patients who underwent both 10 and 30 min WPs, four recurrences occurred (3.8%); three of four were detected at 10 min, yielding 75.0% sensitivity and 99.0% negative predictive value for predicting 30 min recurrence. Right free wall AP location (OR 6.9, CI 1.2-39.2, p = 0.03) and the cumulative procedural risk score (OR 4.3, 95% CI 2.0-10.2, p < 0.001) were significantly associated with WP recurrence in univariable analysis. In follow-up (median 3.3 years [IQR 2.1-4.2]), recurrence was detected in 20 patients (8.6% of the total cohort). Congenital heart disease, right free wall AP location, and cumulative procedural risk score were associated with follow-up recurrence, although the association of the risk score with follow-up recurrence was attenuated in multivariable analysis. CONCLUSIONS: Performing a post-ablation WP provides a modest ARR in 24 h and follow-up AP recurrence. A cumulative procedural risk score may aid in identifying pathways at higher risk of WP recurrence and assist in risk-benefit decision making regarding WP performance and duration. Pathways that recur during the WP are at increased risk of follow-up recurrence.