title: Transcatheter cryothermal ablation of junctional ectopic tachycardia in the normal heart.
abstract: BACKGROUND
  Junctional ectopic tachycardia in the normal heart is rare and often is resistant to pharmacologic management. Transcatheter ablation using radiofrequency energy places the AV node at risk.
  
  
  OBJECTIVE
  The purpose of this study was to report our experience with transcatheter cryothermal ablation using three-dimensional mapping in six patients with junctional ectopic tachycardia.
  
  
  METHODS
  A review of clinical and electrophysiologic data was performed on all patients with structurally normal hearts who underwent cryothermal ablation for treatment of junctional ectopic tachycardia at two institutions.
  
  
  RESULTS
  Six patients (age 7.7-36.5 years) underwent attempted transcatheter cryothermal ablation using three-dimensional mapping. Only one patient had achieved arrhythmia suppression on medical management. Cryothermal mapping (-30 degrees C) localized the junctional focus while normal conduction was monitored. The junctional focus was high in the triangle of Koch in four patients and was low in one patient. The sixth patient had only one run of junctional ectopic tachycardia during the procedure and therefore received an empiric cryoablation (-70 degrees C) lesion. Subsequent cryoablation lesions were delivered at and around the junctional focus. In one patient, cryomapping eliminated the junctional focus but resulted in transient complete AV block; therefore, cryoablation was not performed. All patients who received the cryoablation lesions had elimination of their junctional ectopic tachycardia at 6-week follow-up. The patient who did not receive a cryoablation lesion remained in a slower junctional rhythm at follow-up.
  
  
  CONCLUSIONS
  Cryoablation of junctional ectopic tachycardia is safe and effective. Nonetheless, proximity to the His-Purkinje system may preclude success. Empiric cryoablation can be effective; cryotherapy may not yield immediate success, but a delayed salutary effect can follow.
authors.affiliation: Children's Hospital of Iowa, University of Iowa Hospitals and Clinics, Iowa City, 55242-1083, USA. ian-law@uiowa.edu
authors.forename: Ian H
authors.initials: IH
authors.lastname: Law
authors.forename: Nicholas H
authors.initials: NH
authors.lastname: Von Bergen
authors.forename: Jean C
authors.initials: JC
authors.lastname: Gingerich
authors.forename: Elizabeth V
authors.initials: EV
authors.lastname: Saarel
authors.forename: Peter S
authors.initials: PS
authors.lastname: Fischbach
authors.forename: Macdonald
authors.initials: M
authors.lastname: Dick
mesh_terms: D000293:Adolescent; D000328:Adult; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation; D002648:Child; D003452:Cryosurgery; D015716:Electrocardiography, Ambulatory; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000473:pathology / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional; D007484:Iowa; D008297:Male; D008824:Michigan; D012189:Retrospective Studies; D013613:Tachycardia, Ectopic Junctional / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome