title: The Need for a Lengthier Cryolesion Can Predict a Worse Outcome in 3D Cryoablation of AV Nodal Slow Pathway in Children.
abstract: BACKGROUND
  Transcatheter cryoablation is a well-established technique for the treatment of atrioventricular nodal reentry tachycardia (AVNRT) in children. Nevertheless, atrioventricular nodal slow-pathway conduction may recur after an acutely successful procedure. The aim of this study was to evaluate the long-term outcome of acutely successful AVNRT cryoablations in pediatric patients in case of focal cryolesion and in case of need for High-Density Linear Lesion (HDLL) cryoablation due to focal failure.
  
  
  METHODS
  Sixty-nine consecutive pediatric patients (30 males, mean age 12.4 ± 3.2 years; range: 5.4-18.0 years) underwent 3D-guided cryoablation for AVNRT at our institution from July 2013 to November 2014. When a focal cryoablation was acutely unsuccessful, a 3D-guided HDLL was created delivering multiple overlapping cryolesions/cryoenergy applications from the ventricular side of the tricuspid annulus to the atrial side, including the site of focal cryoablation if transiently successful.
  
  
  RESULTS
  No permanent cryoablation-related complications occurred. Acute success rate was 98.5% (68 out of 69): in 55.9% (38 out of 68) with focal-lesion and in 44.1% (30 out of 68) with HDLL. Mean follow-up was 25.3 months and AVNRT recurrence rate was 13.2% (nine out of 68): 5.2% (two out of 38) with focal lesion and 23.3% (seven out of 30) with HDLL (P = 0.036).
  
  
  CONCLUSIONS
  In cryoablation of AVNRT in children, the need for a more aggressive protocol (HDLL), due to the failure of focal ablation, is strictly related to higher recurrence rates. Indeed, AVNRT recurrences after cryoablation in children seem to be due to a larger and deeper substrate rather than due to the type of energy used.
authors.affiliation: Pediatric Cardiology and Cardiac Arrhythmias/Syncope Unit, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Drago
authors.affiliation: Pediatric Cardiology and Cardiac Arrhythmias/Syncope Unit, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy.
authors.forename: Mario Salvatore
authors.initials: MS
authors.lastname: Russo
authors.affiliation: Pediatric Cardiology and Cardiac Arrhythmias/Syncope Unit, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy.
authors.forename: Irma
authors.initials: I
authors.lastname: Battipaglia
authors.affiliation: Pediatric Cardiology and Cardiac Arrhythmias/Syncope Unit, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy.
authors.forename: Gino
authors.initials: G
authors.lastname: Grifoni
authors.affiliation: Pediatric Cardiology and Cardiac Arrhythmias/Syncope Unit, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy.
authors.forename: Massimo Stefano
authors.initials: MS
authors.lastname: Silvetti
authors.affiliation: Pediatric Cardiology and Cardiac Arrhythmias/Syncope Unit, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy.
authors.forename: Romolo
authors.initials: R
authors.lastname: Remoli
authors.affiliation: Pediatric Cardiology and Cardiac Arrhythmias/Syncope Unit, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Pazzano
authors.affiliation: Pediatric Cardiology and Cardiac Arrhythmias/Syncope Unit, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy.
authors.forename: Fabio Anselmo
authors.initials: FA
authors.lastname: Saputo
authors.affiliation: St. Jude Medical, Agrate Brianza, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Ciani
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003452:Cryosurgery / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D012008:Recurrence; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000601:surgery*; D016896:Treatment Outcome
keywords: atrioventricular nodal reentry tachycardia; children; transcatheter cryoablation