Bridge to success: A better method of cryoablation for atrioventricular nodal reentrant tachycardia in children

BACKGROUND Cryoablation for atrioventricular nodal reentrant tachycardia (AVNRT) is associated with higher recurrence rates than radiofrequency ablation (RFA). Junctional tachycardia marks procedural success with RFA, but no such indicator exists for cryoablation. OBJECTIVE The purpose of this study as to determine the impact of voltage mapping plus longer ablation lesions on midterm success of cryoablation for children with AVNRT. METHODS We performed a single-center retrospective analysis of pediatric patients with AVNRT who underwent cryoablation from 2011 to 2015. Patients ablated using a standard electroanatomic approach (control) were compared with patients ablated using voltage mapping (voltage group). In the voltage group, EnSite NavX navigation and visualization technology (St Jude Medical, St Paul, MN) 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 supraventricular tachycardia. RESULTS In all, 122 patients were included (71 voltage, 51 control). There was no difference between groups regarding age, sex, or catheter-tip size. Short-term success was similar in both groups (98.5% voltage vs 92% control; P = .159), but recurrence rates were lower in the voltage group (0% vs 11%, P = .006). Followup time was shorter in the voltage group (15 +/- 7 months vs 22 +/- 17 months, P < .05). The 1-year freedom from recurrence was lower in the voltage group (100% vs 91.5%, P < . 05). Ablation times were longer in the voltage group (43.7 +/- 20.9 minutes vs 34.3 +/- 20.5 minutes, P = .01), but overall procedure times were shorter in the voltage group (157 +/- 40 minutes vs 198 +/- 133 minutes; P = .018). No significant complication was seen in either group. CONCLUSION Voltage gradient mapping and longer lesion time can decrease recurrence rates in pediatric patients with AVNRT.