Abstract
ABSTRACT
Introduction: Cryoablation is a new alternative to radiofrequency (RF) ablation for treatment of supraventricular tachycardias. A number of key features, such as cryomapping and cryoadhesion, make cryoablation a potentially safer treatment option when working near the AV node. Cryomapping allows the operator to test the ablaton site before an irreversible lesion is made and cryoadhesion provides greater catheter stability. This study describes the clinical experience of cryoablation for atrioventricular nodal reentry tachycardia (AVNRT) at a single centre (BRI, Bristol Royal Infirmary, United Kingdom) and aims to evaluate the safety and efficacy of the procedure.
Methods and results: A total of 149 patients with AVNRT were included (42 men, 107 women, age 45 ± 15 years). The procedure was initiated with a standard electrophysiological study. After confirming a safe location with cryomapping at -30ºC, cryoablation was started. The procedure was successful in 141/149 cases (95%). Complete slow pathway block was achieved in 113/149 cases (76%). Transient AV block was seen in 15/149 patients (10%). No other serious acute complications were seen. 143 patients received a follow-up in the hospital outpatient clinic after 7 ± 5 months. Looking at only the procedures that were initially successful, 107/136 (79%) had no recurrence of their symptoms. An additional 10/136 (7%) said their symptoms had improved. One patient s ECG showed 1° AV block. No other late complications were reported.
Conclusion: Several studies now confirm the safety and efficacy of cryoablation in patients with AVNRT. Whilst the acute success rate is comparable to RF ablation, the long-term success rate is not good as that of RF ablation. No reports of Av block necessitating pacemaker has been made, suggesting that cryoablation should be considered treatment of choice in certain patient groups at high risk of damage to the AV node.