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

<b>Background</b>: Septal accessory pathways (APs) are challenging ablation targets. This study aims to contribute to the pediatric literature by presenting our long-term experience of septal AP ablations with limited fluoroscopy. <b>Methods</b>: This is a retrospective study of all patients who underwent septal AP ablations from July 2012 to July 2023 at a single center. <b>Results</b>: We identified 298 septal AP connections in 291 (11.8 ± 4.9 years) patients. Seventy-nine (27%) cases were diagnosed with supraventricular tachycardia, and 212 (73%) cases were diagnosed with Wolff-Parkinson-White (WPW). The AP locations were posteroseptal (<i>n</i> = 159; 54%), anteroseptal (<i>n</i> = 86; 30%), and midseptal (<i>n</i> = 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%, and of RFA = 94.1%). No statistically significant difference was observed between cryoablation and RFA (<i>p</i> = 0.617). During a mean follow-up of 88.5 ± 33.0 months, the overall recurrence rate was 11.3% (cryoablation vs. RFA; <i>p</i> = 0.834), 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. <b>Conclusions</b>: 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.