Comparison of 6-mm and 8-mm Tip Cryoablation Catheters in the Treatment of Pediatric AVNRT.

BACKGROUND

Radiofrequency (RF) ablation has long been the standard treatment for atrioventricular nodal reentrant tachycardia (AVNRT) in children. However, cryoablation (CA) has gained popularity due to its safety profile and acceptable long-term success rates. Comparative data on different CA catheter tip sizes in pediatric AVNRT are limited.

OBJECTIVE

To compare the acute and long-term outcomes of 6-mm vs. 8-mm tip CA catheters in pediatric patients undergoing AVNRT ablation.

METHODS AND

RESULTS

This retrospective single-center study included 129 pediatric patients (76 female, mean age 13 ± 3.0 years, mean weight 51.7 ± 15.7 kg) who underwent CA for AVNRT between January 2016 and December 2022. A 6-mm tip catheter was used in 64 patients and an 8-mm tip catheter in 65 patients. All procedures were performed using a three-dimensional electroanatomical mapping system (EAMS) (EnSite, Abbott/St. Jude Medical Inc., St. Paul, MN, USA), with minimal or no fluoroscopy in most cases. Acute success, recurrence rates, procedural parameters, and complications were compared between groups. Of the 129 patients, 126 (97.7%) had typical AVNRT and 3 (2.3%) had atypical AVNRT. The mean procedure time was 151.9 ± 43 min, with no significant difference between groups. Acute success rates were 100% in the 6-mm group and 98.5% in the 8-mm group (p > 0.05). The mean number of cryolesions was 8.5 ± 2.3 (6-mm) and 9.0 ± 2.5 (8-mm) (p > 0.05). Over a mean follow-up of 31.4 ± 26 months, recurrences occurred in six patients (4.6%), all successfully re-ablated. Long-term success rates were 94.4% overall, with no significant difference between groups. No permanent complications occurred; transient AV block was observed in one patient (0.7%).

CONCLUSIONS

Both 6-mm and 8-mm CA catheters achieve high acute success and low recurrence rates in pediatric AVNRT with similar safety profiles. Catheter tip size can be tailored to patient age and weight without compromising efficacy. Minimal fluoroscopy approaches can be applied safely in the majority of cases.