16-30: Radiofrequency ablation of right-sided accessory pathways in children: how have 3-D mapping systems and cool-tip catheters changed success, fluoroscopy time and recurrence?

Abstract

Aims: Catheter ablation of right-sided accessory pathways (AP) still presents a challenge with lower success and higher recurrence rates. We evaluated the use of a 3-dimensional mapping (3-D) system in combination with irrigated-tip ablation catheter (ITC) compared to a conventional fluoroscopic/non- irrigated tip catheter approach in patients <18 years undergoing radiofrequency ablation (RFA) for right-sided APs with regard to acute procedural success, fluoroscopy time/dosage, safety and recurrence rate. Methods and results: A retrospective analysis of all patients <18 years undergoing RFA for right-sided APs from May 2004 to December 2014 was performed. In 2010, our approach had changed from conventional fluoroscopy/non- irrigated tip catheters to the use of a 3-D mapping system in combination with irrigated- tip catheter ablation. A total of 105 children (56.2% male) age 4.0–17.9 years (mean 13.4 ± 2.9 years) with 107 right-sided accessory pathways were included in the study. In 15 patients, congenital heart disease was present (Ebstein anomaly n = 8). Preexcitation was overt (n = 75) or concealed (n = 32). AP localization was right free wall (n = 54) or septal (n = 53). The most common AP site was the posteroseptal region (44.9%). Patients were divided into 2 groups. Group 1 included 53 patients (50.5%) undergoing RFA with the use of a 3D mapping system and ITC whereas Group 2 consisted of 52 patients (49.5%) with a conventional fluoroscopic approach/non- irrigated ablation catheter. Study endpoints were acute procedural success rate, fluoroscopy time/dosage, safety and recurrence rate. Radiofrequency catheter ablation was performed acutely successful in 101 of 107 accessory pathways (94.3%). Acute success rates did not differ between Group 1 (94.3%) and Group 2 (94.2%). Procedure time was shorter in the 3-D/ITC Group (mean 129.4 min versus mean 170.9 min; p = 0.001). Fluoroscopy time (mean 12.8 min vs. mean 22.9 min; p = 0.004) and fluoroscopy dose (mean 329.7 cGycm2 vs. mean 756.3 cGycm2 p = 0.009) were also lower in the 3-D/ITC group compared to the conventional group. Overall mortality was 0%. Complications occurred in 5 patients (4.8%) with one major complication in Group 2 (pericardial haemorrhage). Minor vascular complications at the puncture site were observed in 3 patients (2.9%). One patient from Group 2 with a midseptal location pathway developed first-degree atrioventricular block. AP recurrence after an initially successful ablation was observed in 12/101 cases (11.8%). The use of a 3-D system/ITC was associated with a significantly lower AP recurrence rate (6.0% Group 1 vs. 18.4% Group 2; p < 0.05). Conclusion: The use of a 3-D mapping system in combination with irrigated-tip catheter ablation (3-D/ITC) for the ablation of right- sided accessory pathways in children and adolescents is associated with a reduced procedure and fluoroscopy time as well as fluoroscopy dosage. The recurrence rate is significantly lower using 3-D/ITC compared to a conventional approach. The combination of 3-D mapping and irrigated tip catheter ablation might therefore be considered as preferred approach for the ablation of right-sided APs in this age group.