title: Catheter cryoablation of supraventricular tachycardia: results of the multicenter prospective "frosty" trial.
abstract: OBJECTIVE
  To study the safety, efficacy, and mapping utility of a new cryoablation catheter.
  
  
  BACKGROUND
  The CryoCath Technologies Freezor catheter has been used successfully for cryoablation of supraventricular tachycardia (SVT), but has not been evaluated in a large clinical trial.
  
  
  METHODS
  A multicenter clinical trial to evaluate the safety, efficacy, and cryomapping utility of this cryoablation catheter was conducted in 166 subjects. The target of ablation was the slow pathway in patients with SVT due to AV nodal reentry (AVNRT, n = 103), an accessory pathway in patients with AV reentrant SVT (AVRT, n = 51) and the AV junction in patients with atrial fibrillation (AF, n = 12).
  
  
  RESULTS
  Acute procedural success (APS) was achieved in 83% of the overall group (95% CI, 76% to 88%). APS in the AVNRT group was 91% (98.3% CI, 82% to 97%), compared to 69% for AVRT (98.3% CI, 51% to 84%) and 67% for AF (98.3% CI, 29% to 93%), a highly significant difference (P < .001 by stepwise logistic regression). In patients with APS, long-term success after 6 months was 91% overall (95% CI, 86% to 96%) and 94% for AVNRT subjects (98.3% CI, 87% to 100%). None of the AVNRT or AVRT subjects required a permanent pacemaker. Cryomapping successfully identified ablation targets in 64% of patients in whom it was attempted. The electrophysiologic effects of cryomapping were completely reversible within minutes in 94% of such attempts.
  
  
  CONCLUSIONS
  Catheter cryoablation of SVT is a safe alternative to RF ablation and is clinically effective in patients with AVNRT. Cryomapping can reversibly identify targets for ablation and can help minimize the risk of inadvertent AV block during ablation.
authors.affiliation: Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Friedman
authors.forename: Marc
authors.initials: M
authors.lastname: Dubuc
authors.forename: Martin S
authors.initials: MS
authors.lastname: Green
authors.forename: Warren M
authors.initials: WM
authors.lastname: Jackman
authors.forename: David T J
authors.initials: DT
authors.lastname: Keane
authors.forename: Roger A
authors.initials: RA
authors.lastname: Marinchak
authors.forename: Jose
authors.initials: J
authors.lastname: Nazari
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Packer
authors.forename: Allan
authors.initials: A
authors.lastname: Skanes
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Steinberg
authors.forename: William G
authors.initials: WG
authors.lastname: Stevenson
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Tchou
authors.forename: David J
authors.initials: DJ
authors.lastname: Wilber
authors.forename: Seth J
authors.initials: SJ
authors.lastname: Worley
mesh_terms: D000328:Adult; D017115:Catheter Ablation / Q000379:methods*; D016009:Chi-Square Distribution; D003452:Cryosurgery / Q000379:methods*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011446:Prospective Studies; D013617:Tachycardia, Supraventricular / Q000601:surgery*; D016896:Treatment Outcome