title: Cryoablation for presumed atrioventricular nodal reentrant tachycardia in pediatric patients.
abstract: BACKGROUND
  Little data exist on the outcomes of cryoablation for the treatment of presumptive atrioventricular nodal reentrant tachycardia (AVNRT) in a pediatric population.
  
  
  METHODS
  We performed a retrospective chart review of patients undergoing cryoablation from January 2006 to October 2010 for presumed AVNRT at the Children's Hospital Colorado. Inclusion criteria were age ≤ 18, normal heart structure, no prior ablation procedures, documented narrow complex tachycardia, and no inducible tachycardia or other tachycardia mechanisms during electrophysiology study.
  
  
  RESULTS
  Thirteen patients underwent cryoablation for presumed AVNRT. Cryoablation catheter tip size varied from 4 to 8 mm with a median of eight cryoablation lesions. Isoproterenol was utilized preablation in 54% and none postablation. Procedural endpoints, per written report, were loss of sustained slow pathway, change in Wenckebach cycle length, and no specific endpoint. Procedural endpoints, per measured data, were a decrease in patients exhibiting sustained slow pathway conduction. Maximum atrial-His (AH) interval with atrial overdrive pacing was reduced from 266 ms preablation to 167 ms postablation, p = 0.006. The number of patients with an AH jump was reduced from 6 to 2. After follow-up of 13.8 ± 14.3 months, 23% (3/13) had documented tachycardia recurrence. No statistical significance was determined when comparing electrophysiology testing parameters pre- and postablation among the group with recurrence versus the group without recurrence.
  
  
  CONCLUSIONS
  Cryoablation can be considered as a safe alternative to radiofrequency ablation for the treatment of presumed AVNRT among pediatric patients, albeit with a recurrence rate of 23%.
authors.affiliation: Department of Pediatrics, Division of Cardiology, Children's Hospital Colorado, University of Colorado, Aurora, CO 80045, USA.
authors.forename: Mario
authors.initials: M
authors.lastname: Villasenor
authors.forename: Michael S
authors.initials: MS
authors.lastname: Schaffer
authors.forename: Kathryn K
authors.initials: KK
authors.lastname: Collins
mesh_terms: D003452:Cryosurgery / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis* / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult