Bridge to Success: A Better Method of Cryoablation for Atrioventricular Nodal Reentrant Tachycardia in Children.

Cryoablation for AVNRT is associated with higher recurrence rates than radiofrequency ablation(RF). Junctional tachycardia marks procedural success with RF, but no such indicator exists for cryoablation.To determine the impact of voltage mapping plus longer ablation lesions on mid-term success of cryoablation for children with AVNRT.A single-center retrospective analysis was performed of pediatric patients with AVNRT who underwent cryoablation from 2011-2015. Patients ablated using a standard electroanatomic approach(CONTROL) were compared to patients ablated using voltage mapping(VOLTAGE). In the VOLTAGE group, Ensite-NavX was used to develop a "bridge" of lower voltage gradients(0.3-0.8 mV) of the posteroseptal right atrium to guide cryoablation. Kaplan-Meier analysis was used to determine freedom from recurrence of SVT.122 patients were included(71 VOLTAGE, 51 CONTROL). There was no difference between groups with regard to age, gender, or catheter-tip size. Acute success was similar in both groups(98.5% VOLTAGE vs 92% CONTROL; P = 0.159) but recurrence rates were lower in the VOLTAGE group (0% vs. 11%, p=0.006). Follow-up time was shorter in the VOLTAGE group (15±7 months vs 22±17 months, p<0.05). One-year freedom from recurrence was lower in the VOLTAGE group(100% vs. 91.5% , p<0.05). Ablation times were longer in the VOLTAGE group (43.7 ± 20.9 min vs. 34.3 ± 20.5 min, p=0.01), but overall procedure times were shorter in the VOLTAGE group(157±40 vs 198±133 min; p=0.018). No significant complications were seen in either group.Voltage gradient mapping and longer lesion time can decrease recurrence rates in pediatric patients with AVNRT.