Experience and results during transition from radiofrequency ablation to cryoablation for treatment of pediatric atrioventricular nodal reentrant tachycardia

Background: Cryoablation has emerged as a new, theoretically safer, modality for treating atrioventricular nodal reentrant tachycardia (AVNRT). The purpose of this study is to compare procedural aspects and outcomes during the transition from radiofrequency (RF) ablation to cryoablation for pediatric AVNRT. Methods: Data were obtained retrospectively from 80 consecutive pediatric patients who underwent AVNRT ablation from 10/2001- 4/2006 (RF n = 42, Cryo n = 38). Statistical analysis was performed using unpaired t-test, chi-square test, and analysis of variance. Results: RF ablations were performed anatomically in NSR while three different mapping techniques were used during cryoablation: ablation during AVNRT (26%), anatomic in NSR (48%), and anatomic with S ₁ S₂ pacing (26%). There was no difference in the number or duration of lesions between the three cryo subgroups. Acute success was obtained in 95% of RF and 97% of cryo cases. There was no difference in the number of total, mapping, or full-duration lesions between the RF and cryogroups. Despite accounting for longer cryolesion time, total ablation time (P < 0.001), mapping time (P = 0.002), and full duration lesion time (P < 0.001) were longer in the cryogroup. There was no significant difference in total procedure time; fluoroscopy time was shorter in the cryoablation group (P = 0.049). There was one confirmed recurrence of tachycardia in each group with a 2% recurrence rate. Conclusions: Cryoablation for treatment of pediatric AVNRT is as safe and efficacious as RF ablation. Although cryolesions are intrinsically longer in duration, total procedure times were not increased and fluoroscopy times were decreased compared to RF.