Aims: Data about the long-term outcome after cryoablation for atrioventricular nodal reentrant tachycardia (AVNRT) in the paediatric population indicate that recurrence rates are higher with cryo than with radiofrequency energy (RF). The purpose of this study was to review our institutional long-term outcome after cryoablation for AVNRT and to seek for predictors of recurrence.
Methods and results: Forty-nine patients (28 female, age 14 ± 2.7 years) undergoing slow-pathway modulation or ablation for AVNRT at our institution from 2004 to 2008 were included in the study. Acute success was obtained in all patients (100%) with a mean procedure time of 164 ± 50 min and a mean fluoroscopy time of 13 ± 8 min. During a follow-up time of 30 ± 1.9 months, AVNRT recurrence occurred in 11/49 patients (22.4%). Age, sex, number of cryomappings or ablations, catheter tip (4 mm vs. 6 mm), or ablation endpoint (slow-pathway ablation vs. modulation) were not predictive for recurrence. In eight patients, reablation using cryo was performed. All these patients remained free of arrhythmia symptoms during a follow-up of 30 ± 8 months following the second procedure.
Conclusion: Although cryoablation for the treatment for AVNRT in paediatric and adolescent patients is safe and associated with a high acute success rate, AVNRT recurrence occurs in 22% of patients during long-term follow-up without identifiable predictors for recurrence. A second cryoablation procedure leads to a success rate of 100% during long-term follow-up.