title: Transvenous cryoablation versus radiofrequency ablation of the slow pathway for the treatment of atrioventricular nodal re-entrant tachycardia: a prospective randomized pilot study.
abstract: OBJECTIVE
  This is a prospective, randomized study comparing transvenous cryoablation with radiofrequency (RF) ablation of atrioventricular nodal re-entrant tachycardia (AVNRT).
  
  
  RESULTS
  In this pilot trial, 200 patients with AVNRT were randomized to undergo cryoablation or RF ablation of the slow pathway. A 7 Fr 4-mm-tip cryocatheter (Cryocath) was used for cryomapping and cryoablation. Cryomapping was performed at the temperature of -30 degrees C to test the effect on the candidate ablation site. Following successful cryomapping, cryoablation was performed to produce an irreversible lesion by freezing to -75 degrees C. Procedural success, defined as elimination of the slow pathway or noninducibility of AVNRT, was achieved in 97/100 (97%) patients in the Cryo group vs. 98/100 (98%) patients in the RF group. No permanent complete AV-block occurred in either group. During a median of 246 days of follow-up, 8 patients in the Cryo group and 1 in the RF group had AVNRT recurrence. The cumulative incidence of primary endpoint (a combination of procedural failure, permanent complete AV-block and AVNRT recurrence) was significantly higher in the Cryo group than in the RF group (P=0.03, Log-rank test).
  
  
  CONCLUSIONS
  The results of this pilot study indicate that transvenous cryoablation using a 4-mm-tip cryocatheter is associated with a comparable acute success rate but a higher recurrence rate as compared with RF ablation in patients with AVNRT. Potential benefits of cryoablation for ablation of AVNRT need to be determined in a larger multi-centre trial.
authors.affiliation: Deutsches Herzzentrum München und 1. Medizinische Klinik, Klinikum rechts der Isar, Technische Universität München, Lazarettstrasse 36, 80636 Munich, Germany. Zrenner@dhm.mhn.de
authors.forename: Bernhard
authors.initials: B
authors.lastname: Zrenner
authors.forename: Jun
authors.initials: J
authors.lastname: Dong
authors.forename: Jürgen
authors.initials: J
authors.lastname: Schreieck
authors.forename: Isabel
authors.initials: I
authors.lastname: Deisenhofer
authors.forename: Heidi
authors.initials: H
authors.lastname: Estner
authors.forename: Blerim
authors.initials: B
authors.lastname: Luani
authors.forename: Martin
authors.initials: M
authors.lastname: Karch
authors.forename: Claus
authors.initials: C
authors.lastname: Schmitt
mesh_terms: D000328:Adult; D000368:Aged; D017115:Catheter Ablation / Q000379:methods*; D003452:Cryosurgery / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000601:surgery*; D016896:Treatment Outcome