title: Lengthier cryoablation and a bonus cryoapplication is associated with improved efficacy for cryothermal catheter ablation of supraventricular tachycardias in children.
abstract: BACKGROUND
  Cryoablation is an effective treatment for children with supraventricular tachycardias (SVT). The present study documents the effect of two different cryoablation protocols on acute and chronic success rates.
  
  
  RESULTS
  Fifty-three consecutive patients (age range, 5-20 years) were treated; patients 1 to 17 were treated by a standard ablation protocol and patients 18 to 53 were treated by a modified ablation protocol that required lengthier cryoablations plus delivery of a bonus cryoapplication to consolidate the acutely successful irreversible lesion created at intervention. Electrophysiological study (EPS) was performed with diagnostic catheters and cryoablations were performed with a 7FR 4 mm tip catheter (CryoCath Technologies). Acute endpoints for non-inducibility of atrioventricular nodal re-entrant tachycardia (AVNRT) by programmed atrial stimulation at baseline or during isoproterenol performed 30 min post procedure, as well as non-inducibility and conduction block over the accessory pathway (AP). The chronic endpoint was arrhythmia recurrence post intervention. No permanent cryo-related complications or adverse outcomes were reported. Acute success rates for patients 1 to 17 and 18 to 53 were 88 and 100%, respectively. The cumulative percentage of patients without arrhythmia recurrence at 12 month follow-up was significantly different at 73 and 90%, respectively.
  
  
  CONCLUSIONS
  Lengthier cryoablation delivery, approximating 7 min per cryoablation, increases the acute success rate at intervention. Moreover, these lengthier cryoablation deliveries plus a bonus cryoapplication to consolidate the acutely successful irreversible lesion created at intervention may also significantly improve the chronic success rate, while also maintaining an excellent safety profile for cryoablation treatment of children with SVT such as AVNRT and AP located near the AV junction.
authors.affiliation: Department of Pediatric Cardiology, Bambino Gesù Hospital, Rome, Italy. drago@opbg.net
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Drago
authors.forename: Massimo Stefano
authors.initials: MS
authors.lastname: Silvetti
authors.forename: Antonella
authors.initials: A
authors.lastname: De Santis
authors.forename: Giorgia
authors.initials: G
authors.lastname: Grutter
authors.forename: Peter
authors.initials: P
authors.lastname: Andrew
mesh_terms: D000293:Adolescent; D000328:Adult; D017115:Catheter Ablation / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D003452:Cryosurgery / Q000379:methods*; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D008297:Male; D013617:Tachycardia, Supraventricular / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome