title: Cryoablation versus radiofrequency ablation for treatment of pediatric atrioventricular nodal reentrant tachycardia: initial experience with 4-mm cryocatheter.
abstract: BACKGROUND
  Initial reports have shown cryoablation to be safe and efficacious for treatment of atrioventricular nodal reentrant tachycardia (AVNRT). No direct comparisons of cryoablation vs radiofrequency (RF) catheter ablation in pediatric patients have been made.
  
  
  OBJECTIVE
  The purpose of this study was to compare the outcomes of cryothermal vs RF catheter ablation for treatment of AVNRT in pediatric patients.
  
  
  METHODS
  We retrospectively reviewed consecutive ablation procedures for treatment of AVNRT at a single arrhythmia center. The RF group consisted of patients who underwent RF ablation from 2002 until cryothermy became available. The cryoablation group consisted of patients who underwent cryothermal ablation from 2004 to 2005. The groups were compared for procedural and electrophysiologic outcomes.
  
  
  RESULTS
  RF (n = 60, age 14 +/- 4 years) and cryoablation (n = 57, age 14 +/- 4 years) groups had similar demographic and baseline parameters. Procedural times were shorter in the RF group (RF ablation 112 +/- 31 minutes vs cryoablation 148 +/- 46 minutes, P < .001). Fluoroscopy times were comparable (RF ablation 21 +/- 15 minutes vs cryoablation 20 +/- 13 minutes, P = .77). In an intention-to-treat analysis, success of the procedure was 100% for RF ablation and 95% for cryoablation (P = .11). No permanent AV block occurred in either group. Recurrence rates were higher for the cryoablation group, but this did not reach statistical significance (RF ablation 2% vs cryoablation 8%, P = .19).
  
  
  CONCLUSIONS
  Cryoablation appears to be similar to RF for ablation of AVNRT with respect to short-term efficacy and safety of the procedure in a pediatric population. Recurrence rates are higher with cryoablation.
authors.affiliation: Division of Cardiology, Department of Pediatrics, University of California, San Francisco, California 94143-0632, USA. kathryn.collins@ucsf.edu
authors.forename: Kathryn K
authors.initials: KK
authors.lastname: Collins
authors.forename: Anne M
authors.initials: AM
authors.lastname: Dubin
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Chiesa
authors.forename: Kishor
authors.initials: K
authors.lastname: Avasarala
authors.forename: George F
authors.initials: GF
authors.lastname: Van Hare
mesh_terms: D000293:Adolescent; D017115:Catheter Ablation / Q000009:adverse effects; D002648:Child; D003452:Cryosurgery / Q000009:adverse effects / Q000295:instrumentation; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006327:Heart Block / Q000209:etiology; D006801:Humans; D008297:Male; D012008:Recurrence; D012189:Retrospective Studies; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome