Cryoablation of typical atrioventricular nodal reentrant tachycardia in children: six years' experience and follow-up in a single center.

BACKGROUND: Cryoablation is an effective and safe treatment for children with supraventricular tachycardias when the reentry circuit is located near the atrioventricular (AV) junction. We retrospectively reviewed consecutive cryoablation procedures for the treatment of atrioventricular nodal reentrant tachycardia (AVNRT) in children and young adults in a single pediatric center. METHODS: From October 2002 to October 2008, cryoablation was attempted in 76 pediatric patients (mean age 11.3 +/- 2.4 years, range: 6-16.4 years) with symptomatic typical AVNRT. Cryomapping, used to identify the tissue site for safe arrhythmia ablation, was performed at -30 degrees C for a maximum of 60 seconds. The efficacy of the cryomapping procedure was assessed in terms of disappearance of dual-AV node physiology and noninducibility of AVNRT. RESULTS: Cryoablations were from 4 to 8 minutes long at -75 degrees C. A single "bonus" cryoapplication (-75 degrees C for minimum 6 minutes) was delivered to consolidate the acutely successful cryoablation for 64 consecutive patients. After the cryoablation procedure, patients were assessed at 1, 3, 6, 12, 18, and 24 months (and then every year thereafter) by a clinical evaluation and standard electrocardiogram, Holter monitoring, and exercise stress testing. No permanent cryo-related complications were reported. Seventy-four (97.4%) patients were successfully acutely ablated. During a mean follow-up of 29.5 months (range 2-74 months), five (6.8%) acutely successful pediatric patients experienced arrhythmia recurrence. We did not identify any predictive factors of AVNRT recurrence. CONCLUSIONS: Acute and long-term results demonstrate that cryoablation of AVNRT can be considered a safe and effective procedure in pediatric patients. (PACE 2010; 475-481).