Impact of cryoablation catheter size on success rates in the treatment of atrioventricular nodal re-entry tachycardia in 160 patients with long-term follow-up

Abstract

Aims: To determine the efficacy and safety of cryoablation for the treatment of atrioventricular nodal re-entry tachycardia (AVNRT).

Methods and results: We analysed the procedural characteristics, acute success, and recurrence rates of 160 consecutive patients treated with cryoablation for the AVNRT and followed up for 18 months. Mean procedural time was 119.1 +/- 3.7 min, with an average of 4.6 +/- 0.2 Cryo lesions and an acute procedural success rate of 93%. Recurrence rates were 19 (11.9%) cases and were significantly higher in the 4 mm cryocatheter-treated group (12/59, 16.9%), compared with the 6 mm cryocatheter-treated group (9/101, 6.9%, P = 0.01). Recurrence rates were greater where slow pathway block was not achieved 8/12 (66.7%), compared with complete slow pathway block 11/129 (8.5%, P < 0.0001). Recurrence was significantly more likely if atrial echo beats were still present after cryoablation, 12/130 (9.2%) patients with no recurrence vs. 7/19 (36.8%) patients with recurrence (P < 0.0001).

Conclusion: Cryoablation is a safe and efficacious treatment for AVNRT. Complete slow pathway block is associated with long-term success, together with the use of the larger 6 mm cryocatheter. There is always a risk of heart block with radiofrequency ablation, although this experience confirms previous findings that the risk with Cryo is zero.