RESUMO
PURPOSE: Radiofrequency ablation (RF) of atrioventricular reentrant tachycardia (AVNRT) is an effective method for treating this arrhythmia. However, inadverted AV block requiring implantation of permanent pacemaker is a worrisome side effect. Although permanent AV block seems to be rare nowadays, patients are by no means spared from this severe complication. Catheter cryoablation is emerging as an alternative technology with an excellent safety profile, but limited data exist regarding its efficacy. METHODS: We conducted a randomized study among patients with AVNRT remitted to our center for EP study and ablation between January 2008 and June 2010. After giving a written consent, patients were randomized to conventional RF or cryoablation, unless specific preference of patient was stated. Primary outcomes were acute success, SVT recurrence, and complications, including AV block. RESULTS: One hundred nineteen patients were included (60 cryoablation and 59 conventional RF). There were no differences in demographic and clinical baseline data between groups. Acute procedural success was achieved in 59 patients (98 %) in cryoablation group and 59 (100 %) in RF. One patient in RF group underwent complete AV block and pacemaker implantation. Over a mean follow-up period of 256.6 days, there was a significant difference in AVNRT recurrence between cryoablation and RF patients (15 versus 3.4 %, p = 0.03). CONCLUSION: Catheter cryoablation of AVNRT is a clinically effective alternative to RF ablation, with excellent acute success rate. Despite a slightly higher rate of recurrence during long-term follow-up, these results suggest that cryoablation may be considered as first-line approach, especially in younger people, where the risk of permanent pacing because of inadvertent AV block may be relevant.