Slow pathway elimination for atrioventricular nodal reentrant tachycardia with the 8-mm tip cryoablation catheter: an 18-month follow-up study.

Purpose: The 9-French 8-mm tip cryoablation catheter confers a high rate of acute slow pathway (SP) elimination and an acceptable short-term outcome in patients with atrioventricular nodal reentrant tachycardia (AVNRT). The aim of this study was to investigate the long-term outcome of patients treated with this electrode in this indication.

Methods: Eighty-two patients (female = 52) with a mean age of 54.9 ± 17.7 years underwent SP elimination for typical AVNRT with the 8-mm tip cryocatheter in our institution between November 2009 to June 2012. Clinical and procedural characteristics were prospectively collected.

Results: Acute procedural success defined as AVNRT non-inducibility at the end of the procedure was obtained in 81/82 patients (98.7 %). Mean procedure duration and fluoroscopy time were 74.4 ± 28.7 min (range, 35-160 min) and 8.7 ± 5.3 min (range, 2-26 min), respectively. Mean number of energy applications was 4.0 ± 2.4 (range, 2-15). No permanent atrioventricular block was observed. Transient atrioventricular block occurred in 12 patients (14.6 %). Traumatic fast pathway conduction block occurred in one patient before cryoenergy delivery. Using an intention-to-treat analysis, 78 patients (95.1 %) remained free of AVNRT recurrence during a mean follow-up of 17.8 ± 9.3 months.

Conclusions: This study confirmed that the 8-mm tip cryocatheter is both safe and highly effective for SP conduction elimination in patients with AVNRT and demonstrated a low recurrence rate during a long-term follow-up.