Treatment of atrioventricular nodal re-entrant tachycardia by cryoablation with an 8-mm-tip catheter versus radiofrequency ablation.

Purpose: Catheter cryoablation (CRYO) may eliminate inadvertent atrioventricular block (AVB) in the treatment of atrioventricular nodal reentrant tachycardia (AVNRT). However, higher recurrence was observed with CRYO delivered by 4 mm or 6 mm-tip catheter. This study was performed to investigate whether a comparably low treatment failure and recurrence rate as in radiofrequency (RF) ablation is achievable by CRYO with an 8-mm-tip catheter.

Methods: This is a retrospective case-control study including 40 patients with AVNRT treated with CRYO (n = 20) using an 8 mm-tip catheter or RF ablation (n = 20) from March 2009 to March 2011. Treatment failure was defined as the composite of acute procedural failure including inadvertent permanent AVB and documented recurrence.

Results: Acute procedural success of 90% (18/20) and 95% (19/20) were achieved in CRYO and RF ablation group, respectively (p = 0.998), with no permanent AVB in either group. With Kaplan-Meier analysis, there was no significant difference between the treatment groups in terms of recurrence rate (5.6% [1/18] vs. 0%; log-rank test p = 0.304) and treatment failure (15% [3/20] vs. 5% [1/20]; log-rank test p = 0.301). Shorter fluoroscopy time (15 ± 8.6 vs. 25.2 ± 12.1 min; p = 0.005) and more energy applications (median 4 [2-15] vs. 2 [1-8]; p = 0.005) were observed in the CRYO group compared with RF ablation group.

Conclusions: Compared to RF ablation, CRYO with an 8-mm-tip catheter for treating AVNRT achieves a comparable acute procedural success, comparably low recurrence rate and composite endpoint of treatment failure. Shorter fluoroscopy time and more energy applications were observed in the CRYO group.