Current trends in outcome of thermal catheter ablation for accessory pathways: A retrospective, single center study of 500 children and adults

Abstract Purpose This study aimed to describe updated trends in patient characteristics, procedure efficacy and safety in patients with accessory pathway (AP) treated with catheter ablation using thermal ablation in a single center in Denmark. Methods This retrospective single-center cohort study included 500 patients with AP who underwent catheter ablation with thermal energy at Rigshospitalet, Copenhagen from 2019-2024 (565 procedures). Data was collected from electronic patient records until 1 st of October 2024, and in a subset until May 2025. Median follow-up time was 191 days. Results Most patients were males (290, (58%)), and at the time of first ablation the mean age was 26 years; 217 patients (43%) were below 18 years. Acute procedural success was achieved in 464 patients (92.8%), of whom recurrence occurred in 49 patients (10.7%) during follow-up. Septal AP was associated with lower acute success (OR=0.22, p=0.003) compared to non-septal AP. Predictors for later recurrence was septal AP (14%, OR=3.21, p=0.005), right non-septal AP (27.8%, OR=9.5, p<0.00001), and multiple APs (33.3%, OR=7.6, p=0.002), compared to left non-septal AP (4.9%). Woman had significantly lower odds of recurrence compared to men (OR=0.36, p=0.008). One patient developed complete atrio-ventricular-block (AV-block) and two cases of cardiac tamponade were seen. Conclusion Catheter ablation of AP using thermal energy remains a highly effective and safe treatment for both pediatric and adult patients. However, despite improved technology, septal and right-sided pathways remain predictors for later recurrence.