Low Recurrence Rate in Treating Atrioventricular Nodal Reentrant Tachycardia with Triple Freeze‐Thaw Cycles

Abstract

Cryoablation is an alternative to radiofrequency ablation in treating atrioventricular nodal reentrant tachycardia (AVNRT). However, its long-term effectiveness is in question when compared to radiofrequency ablation. We reviewed the results of cryoablation in children with AVNRT at our institute. We performed a retrospective single-center chart review of consecutive patients ≤18 years of age with AVNRT who underwent cryoablation between January 2007 and August 2009. During cryoablation, a 6-mm-tip cryocatheter was used with temperature set to -80°C. Test lesions were performed at the presumed slow pathway location based on combined anatomic and electrophysiologic approach. If successful, ablation was then continued with triple freeze-thaw cycles (FTC) of 4 minutes each. A total of 53 patients (age range: 6.1-18.4 years, mean: 13.6 years, median: 13.2 years) underwent slow pathway modification with cryoablation. Acute success was achieved in 51 (96.2%) cases. Transient atrioventricular block was seen in 19 cases. The block occurred during FTC in eight patients (15%). The number of FTC was three in 47 (92.2%) patients. Less than three FTC were given in two patients due to transient heart block and four FTC were given in two patients with suspected catheter movement. Procedure duration was 177 ± 56 minutes; fluoroscopic time was 14 ± 11 minutes. Mean follow-up was 30.7 ± 10 (range 12-52, median 31) months. Recurrence of supraventricular tachycardia was seen in only one (1.96%) patient. Triple FTC cryoablation lesions resulted in a low recurrence rate comparable to RF ablation in treating AVNRT without increased complications.