title: Electroanatomic mapping guided cryoablation of Mahaim pathways in children with limited fluoroscopy exposure.
abstract: BACKGROUND
  The presence of Mahaim accessory pathways (MAP) with anterograde decremental conduction is a disorder that leads to antidromic atrioventricular reentrant tachycardia. There are rare reports of cryoablation use in MAP. This study aims at sharing our experience with using cryoablation to treat MAP in children.
  
  
  METHODS
  Electrophysiology study and catheter ablation were performed in 14 patients diagnosed with Mahaim tachycardia between January 2010 and December 2013. Cryoablation was used in nine of the cases. A three-dimensional navigation system with surface electrode patches (EnSite System, St. Jude Medical Inc., St. Paul, MN, USA) was used for all procedures.
  
  
  RESULTS
  The patients (two girls and seven boys) had a median age of 11.5 years (8-18 years) and a median weight of 67 kg (31-80 kg). Mahaim conduction was localized in the right posterolateral (n = 4), right lateral region (n = 2), right posteroseptal (n = 1), right anterolateral (n = 1), and right anterior (n = 1). A pathway potential was noted in six of nine cases at the tricuspid annulus. Catheter choices and acute success rates were as follows: cryoablation in four (three of four successful), radiofrequency catheter ablation (RFA) and cryoablation in five (successful in four of five). No fluoroscopy was used in six of nine patients. The mean procedure duration was 249 ± 90 minutes. No major complications were observed. The final long-term success rate for cryoablation was seven of nine (78%).
  
  
  CONCLUSIONS
  Cryoablation can be used as a reliable and effective alternative to RFA in the treatment of Mahaim accessory conduction pathways in children. Prospective comparative studies are necessary in order to further evaluate the long-term efficacy of this method.
authors.affiliation: Mehmet Akif Ersoy Cardiovascular Research and Training Hospital, Istanbul, Turkey.
authors.forename: Erkut
authors.initials: E
authors.lastname: Ozturk
authors.forename: Yakup
authors.initials: Y
authors.lastname: Ergul
authors.forename: I Cansaran
authors.initials: IC
authors.lastname: Tanidir
authors.forename: Celal
authors.initials: C
authors.lastname: Akdeniz
authors.forename: H Tahsin
authors.initials: HT
authors.lastname: Tola
authors.forename: Volkan
authors.initials: V
authors.lastname: Tuzcu
mesh_terms: D058606:Accessory Atrioventricular Bundle / Q000503:physiopathology / Q000601:surgery*; D000293:Adolescent; D002648:Child; D003452:Cryosurgery / Q000379:methods*; D004452:Echocardiography; D015716:Electrocardiography, Ambulatory; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005471:Fluoroscopy; D006329:Heart Conduction System / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D011227:Pre-Excitation, Mahaim-Type / Q000503:physiopathology / Q000601:surgery*; D013686:Telemetry; D016896:Treatment Outcome
keywords: Mahaim pathways; children; cryoablation; electroanatomical mapping