Europace Advance Access originally published online on March 5, 2009
Europace 2009 11(5):630-634; doi:10.1093/europace/eup045
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Electrophysiology and Ablation
‘Time to effect’ during cryomapping: a parameter related to the long-term success of accessory pathways cryoablation in children
1 Paediatric Cardiology Department, Bambino Gesù Hospital, Piazza Sant’Onofrio 4, 00165 Rome, Italy; 2 Clinical and Experimental Department of Medicine and Pharmacology, University of Messina, Messina, Italy; 3 Faculty of Statistic Sciences, University of Messina, Messina, Italy
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.
Key Words: Supraventricular tachycardia, Accessory pathway, Children, Cryoablation
* Corresponding author. Tel: +39 06 68592171, Fax: +39 06 68592257, Email: drago{at}opbg.net
Manuscript submitted 21 October 2008. Accepted after revision 31 January 2009.