title: Cryoablation of atrioventricular nodal reentrant tachycardia in children and adolescents: improved long-term outcomes with increasing experience.
abstract: BACKGROUND
  Cryoablation is increasingly used for the treatment of atrioventricular nodal reentrant tachycardia (AVNRT). There are limited data regarding its efficacy and late outcomes in the pediatric population.
  
  
  METHODS
  We reviewed the clinical records of 70 consecutive pediatric and adolescent patients (mean age: 12.2 ± 3, range: 5-19 years) with AVNRT, with or without additional structural heart disease, who underwent catheter ablation with the intention to use cryoablation as the primary modality between September 2004 and July 2011.
  
  
  RESULTS
  The acute success rate was 97.14%. No long-term complications occurred. Patients were followed up for an average time of 46 ± 22.5 months (range 5-90). The recurrence rate was 16%, decreasing from 28% in the first 25 cases to 8.9% in the last 45 cases (p<0.05). Wenckebach point prolongation during cryoapplications was associated with a lower recurrence rate (p<0.05). No other risk factors for recurrence were identified, including persistence of slow pathway conduction. Patients with congenital heart disease had a similar success rate to patients with a structurally normal heart.
  
  
  CONCLUSIONS
  When applied to pediatric patients, cryoablation has an excellent success and safety profile, which can improve with increasing experience. Transient Wenckebach point prolongation during cryo-applications may be associated with improved late outcomes.
authors.affiliation: Division of Pediatric Cardiology, Mitera Children's Hospital, Athens, Greece.
authors.forename: Christos
authors.initials: C
authors.lastname: Cokkinakis
authors.forename: Dimosthenis
authors.initials: D
authors.lastname: Avramidis
authors.forename: Chrysanthos
authors.initials: C
authors.lastname: Alexopoulos
authors.forename: George
authors.initials: G
authors.lastname: Kirvassilis
authors.forename: John
authors.initials: J
authors.lastname: Papagiannis
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003452:Cryosurgery / Q000009:adverse effects / Q000379:methods*; D005500:Follow-Up Studies; D006801:Humans; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult