title: Treatment of atrioventricular nodal re-entrant tachycardia by cryoablation with a 6 mm-tip catheter vs. radiofrequency ablation.
abstract: OBJECTIVE
  To compare recurrence rate and other procedural characteristics in patients undergoing atrioventricular nodal re-entrant tachycardia (AVNRT) treatment with catheter cryoablation (CRYO) delivered by 6 mm-tip catheter or radiofrequency (RF) ablation.
  
  
  RESULTS
  This is a retrospective case-control study including 80 patients with AVNRT treated with CRYO from March 2002 to June 2008. They were compared with another 80 consecutive patients who underwent RF ablation for AVNRT within the same period. Procedural success of 97.5 and 95% were achieved in CRYO and RF group, respectively. There was no permanent atrioventricular block (AVB) in the CRYO group, whereas two (2.5%) patients developed permanent first-degree or second-degree AVB in RF group (P = 0.155). Higher recurrence was found in the CRYO group (9 vs. 1.3%; P = 0.032) with no difference in the composite endpoint of procedural failure and recurrence between the groups (P = 0.263). There was significantly shorter fluoroscopy time (18.6 +/- 10.8 vs. 25.9 +/- 17.0 min; P = 0.002) and more energy applications required (3.1 +/- 1.7 vs. 1.9 +/- 1.1; P < 0.001) in the CRYO than the RF group.
  
  
  CONCLUSIONS
  Compared with RF ablation, CRYO with 6 mm-tip catheter for treating AVNRT results in higher recurrence and potentially lower incidence of permanent AVB. Fluoroscopy time has been shown to be reduced by CRYO.
authors.affiliation: Princess Margaret Hospital, 2-10 Princess Margaret Hospital Road, Lai Chi Kok, Kowloon, Hong Kong. ngaiyinchan@yahoo.com.hk
authors.forename: Ngai Yin
authors.initials: NY
authors.lastname: Chan
authors.forename: Ngai Shing
authors.initials: NS
authors.lastname: Mok
authors.forename: Chun Leung
authors.initials: CL
authors.lastname: Lau
authors.forename: Ying Keung
authors.initials: YK
authors.lastname: Lo
authors.forename: Chi Chung
authors.initials: CC
authors.lastname: Choy
authors.forename: Suet Ting
authors.initials: ST
authors.lastname: Lau
authors.forename: Yuen Choi
authors.initials: YC
authors.lastname: Choi
mesh_terms: D017115:Catheter Ablation / Q000295:instrumentation* / Q000379:methods*; D003452:Cryosurgery / Q000295:instrumentation* / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis / Q000628:therapy*; D016896:Treatment Outcome