Cryoablation for AVNRT: Importance of Ablation Endpoint Criteria

BACKGROUND: For ablation of atrioventricular nodal reentrant tachycardia (AVNRT), cryoablation has been shown to be a safe alternative to radiofrequency ablation. However, previous studies have shown a higher recurrence rate with cryoablation compared to radiofrequency ablation. OBJECTIVE: This study reviewed our experience using cryoablation for typical AVNRT using stringent endpoint criteria for slow pathway ablation, yet preserving the desirable safety profile of cryoablation. METHODS: Seventy-five consecutive cases of typical AVNRT underwent cryoablation. Ablation of the AV nodal slow pathway was performed with the goal of eliminating tachycardia, AH jump, and retrograde atrial echo beats. The primary efficacy endpoint was freedom of recurrent supraventricular tachycardia at follow-up. Analysis of AVN characteristics, number of lesions, and complications was performed. RESULTS: Seventy-two (96%) patients met the primary efficacy endpoint over an average follow-up of 34.6 (12.6-68.3) months. In patients who had complete elimination of the slow pathway, there were no recurrences. The presence of an AH jump with a single retrograde echo was highly associated with a recurrence (P = 0.0001). There were no complications, including AV conduction block. CONCLUSION: The efficacy of cryoablation for management of AVNRT can be comparable to radiofrequency energy if the suggested endpoint of elimination of tachycardia, AH jump with retrograde atrial beats, is met. Prior studies evaluating cryoablation in this setting did not require this endpoint, which could have contributed to the relatively higher rate of late recurrences.