title: Cryoablation compared with radiofrequency ablation for atrioventricular nodal re-entrant tachycardia: analysis of factors contributing to acute and follow-up outcome.
abstract: OBJECTIVE
  The efficacy of transvenous Cryoablation (Cryo), for the treatment of atrioventricular nodal re-entry tachycardia (AVNRT), when compared with radiofrequency (RF) ablation, requires further investigation.
  
  
  RESULTS
  We sought to compare the acute- and follow-up results of 71 cases each of Cryo and RF for AVNRT using a retrospective matched case-control study design and aimed at identifying patient and procedural factors that may predict success with each strategy. Primary failure of Cryo (thus necessitating RF at the same sitting) was seen in 11 (15.4%) cases, whereas there were two (2.8%) primary failures with RF (P<0.01). Patients in the Cryo group had significantly higher arrhythmia recurrence [14 (19.8%)] when compared with the RF group [4 (5.6%)] (P<0.01). The incidence of recurrence following Cryo was significantly higher if an echo beat was still inducible after ablation than if complete slow pathway block was achieved (7/19, vs. 4/46, P<0.001). The median number of Cryo lesions was significantly lower in patients who had recurrence compared with those who did not (1.5 vs. 3.0, P=0.02).
  
  
  CONCLUSIONS
  We have observed a much higher primary failure and recurrence rate with Cryo when compared with RF for AVNRT. It may be possible to decrease this high recurrence rate by aiming to achieve complete slow pathway block and by increasing the number of Cryo lesions.
authors.affiliation: Department of Cardiology, First Floor, Dominion House, 60 Bartholomew Close, St Bartholomew's Hospital, West Smithfield, London EC1A 7BE, UK.
authors.forename: Dhiraj
authors.initials: D
authors.lastname: Gupta
authors.forename: Rasha K
authors.initials: RK
authors.lastname: Al-Lamee
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Earley
authors.forename: Peter
authors.initials: P
authors.lastname: Kistler
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Harris
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Nathan
authors.forename: Simon C
authors.initials: SC
authors.lastname: Sporton
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Schilling
mesh_terms: D000328:Adult; D000368:Aged; D001283:Atrioventricular Node / Q000601:surgery; D017115:Catheter Ablation; D003452:Cryosurgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000601:surgery*; D016896:Treatment Outcome