Catheter Ablation of Septal Accessory Pathways in Children: A 12- Year Experience at a Tertiary Care Center

Background: Septal accessory pathways (APs) are challenging ablation targets. The study aims to contribute to the pediatric literature by presenting our long-term experience of septal AP ablations with limited fluoroscopy. Methods: This is a retrospective study of all patients who underwent septal AP ablations from July 2012 to July 2023 at a single center. Results: We identified 298 septal AP connections in 291 (11.8 ± 4.9 years) patients. Seventy-nine (27%) cases were diagnosed with supraventricular tachycardia, and 225 (73%) cases were diagnosed with Wolff-Parkinson-White syndrome (WPW). The AP locations were posteroseptal (n=159;54%), anteroseptal (n=86;30%), and midseptal (n=46;16%). Of those diagnosed with WPW, 61 (28%) had high-risk AP and 90 (40%) were adenosine responsive. Cryoablation was used in 190 (66%), radiofrequency ablation (RFA) was used in 36 (12.5%), and both were used in 62 (21.5%) patients. The overall acute success rate of initial procedures was 89.6% (The acute success rate of cryoablation=86.6%; RFA=94.1%). During a mean follow-up of 88.5±33.0 months, the overall recurrence rate was 11.3%, with the highest at the right-posteroseptal location. An irrigated-tip RFA was preferred during redo procedures in 20 (45%) cases. The long-term success rate was 99% when the repeat procedures were considered. No complications were observed. Conclusions: Due to the higher recurrence rates in septal AP ablations compared to other locations, repeated procedures might be needed to achieve definitive long-term success. This study indicates that similar acute and long-term success rates can be achieved with cryoablation compared to RFA, with the significant benefit of increased safety.