A Single 480‐s Cryoablation Reduces Long‐Term Arrhythmia Recurrence Rate Than Standard Cryoablation in Patients With AVNRT

INTRODUCTION Focal cryoablation (CRYO) is an alternative to radiofrequency ablation (RFA) in patients with atrioventricular nodal reentrant tachycardia (AVNRT) with low risk of atrioventricular (AV) block and high arrhythmia recurrence. There are limited studies showing that longer duration and bonus CRYO decreases arrhythmia recurrence compared to standard CRYO (two times 240 s). In our study, it was planned to investigate the efficacy of a single 480-s CRYO protocol on the long-term risk of AVNRT recurrence and persistent AV block in AVNRT patients compared to standard CRYO and RFA protocols.

METHODS Two hundred sixty patients who underwent ablation for AVNRT were enrolled in this retrospective cohort study. Patients were divided into three groups: standard CRYO group (Group I), single 480-s CRYO group (Group II), and RFA group (Group III). Groups I, II, and III included 92, 68, and 100 AVNRT patients, respectively. Patients were followed for 32 ± 9.1 months after ablation. The groups were compared for acute process success, transient AV block, persistent AV block, and long-term arrhythmic recurrence.

RESULTS In the follow-up, AVNRT recurrence was determined in 10, 2, and 3 patients in Groups I, II, and III, respectively (p < 0.001). The frequency of AVNRT recurrence was significantly higher in Group I than in Groups II and III (p < 0.05). It was found that the frequency of AVNRT recurrence was similar between Groups II and III. In Groups I and II, permanent AV block associated with ablation was not observed in either case. However, in Group III, only two patients were found to have permanent AV block. There were no statistical differences between groups in terms of permanent AV block development. Acute process success and transient AV block development were similar among groups.

DISCUSSION In our study, it was shown that AVNRT patients can be treated effectively and safely with a single 480-s CRYO protocol among catheter ablation methods. While this new CRYO protocol significantly reduces the long-term arrhythmic recurrence rate compared to standard CRYO, it is similarly effective with RFA.