'Time to effect' during cryomapping: a parameter related to the long-term success of accessory pathways cryoablation in children

• Published in: Europace (London, England) England), 2009-05, Vol.11 (5), p.630-634
• Main Authors: Drago, Fabrizio, Russo, Mario Salvatore, Silvetti, Massimo Stefano, De Santis, Antonella, Naso Onofrio, Maria Teresa
• Format: Article
• Language: English
• Subjects: Adolescent; Child; Child, Preschool; Cryosurgery - methods; Electrocardiography; Female; Heart Conduction System - physiopathology; Humans; Male; Predictive Value of Tests; Prognosis; Retrospective Studies; ROC Curve; Sensitivity and Specificity; Tachycardia, Supraventricular - diagnosis; Tachycardia, Supraventricular - physiopathology; Tachycardia, Supraventricular - surgery; Time Factors; Treatment Outcome
• ISSN: 1099-5129; 1532-2092
• DOI: 10.1093/europace/eup045

Aims Cryoablation is an effective treatment for children with an accessory pathway (AP). Nevertheless, AP may recur after a successful procedure. The aim of this study was to identify the factors predictive of AP recurrence. Methods and results Thirty patients (mean age 12.6 ± 2.9 years) with acutely successful cryoablation of supraventricular tachycardia caused by a right-sided AP were studied. In 20 patients, a lengthier cryoablation and a single 'bonus' cryoapplication to consolidate a permanent lesion were delivered. During the follow-up (mean duration 20 months, range 4-25), no permanent cryo-related complications occurred. Accessory pathway recurrence was observed in six patients (20%) overall, specifically in 30% of patients who did not undergo a bonus cryoapplication and in 15% of the others. The likelihood of AP recurrence was correlated with the 'time to effect' (TTE), i.e. the time interval between the onset of cryomapping at −30°C and the disappearance of AP conduction. The mean TTE in the patients without AP recurrence was 8.2 ± 8.4 s, in contrast with 16.7 ± 9.8 s in the others (P = 0.04). The receiver-operating characteristic (ROC) curve of TTE values demonstrates that if the pathway does not lose its conduction capacity until 10 s after reaching −30°C, the probability of arrhythmia recurrence is higher (area under curve = 0.767, sensitivity 83.3%, and specificity 66.7%). Conclusion The long-term success of cryoablation of right-sided AP is closely correlated to the TTE during cryomapping.