title: Impact of cryoablation catheter size on success rates in the treatment of atrioventricular nodal re-entry tachycardia in 160 patients with long-term follow-up.
abstract: OBJECTIVE
  To determine the efficacy and safety of cryoablation for the treatment of atrioventricular nodal re-entry tachycardia (AVNRT).
  
  
  RESULTS
  We analysed the procedural characteristics, acute success, and recurrence rates of 160 consecutive patients treated with cryoablation for the AVNRT and followed up for 18 months. Mean procedural time was 119.1 +/- 3.7 min, with an average of 4.6 +/- 0.2 Cryo lesions and an acute procedural success rate of 93%. Recurrence rates were 19 (11.9%) cases and were significantly higher in the 4 mm cryocatheter-treated group (12/59, 16.9%), compared with the 6 mm cryocatheter-treated group (9/101, 6.9%, P = 0.01). Recurrence rates were greater where slow pathway block was not achieved 8/12 (66.7%), compared with complete slow pathway block 11/129 (8.5%, P < 0.0001). Recurrence was significantly more likely if atrial echo beats were still present after cryoablation, 12/130 (9.2%) patients with no recurrence vs. 7/19 (36.8%) patients with recurrence (P < 0.0001).
  
  
  CONCLUSIONS
  Cryoablation is a safe and efficacious treatment for AVNRT. Complete slow pathway block is associated with long-term success, together with the use of the larger 6 mm cryocatheter. There is always a risk of heart block with radiofrequency ablation, although this experience confirms previous findings that the risk with Cryo is zero.
authors.affiliation: Department of Cardiology, Bristol Royal Infirmary, Level 4, Dolphin House, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, UK.
authors.forename: Alistair
authors.initials: A
authors.lastname: Sandilands
authors.forename: Philip
authors.initials: P
authors.lastname: Boreham
authors.forename: Jonathan
authors.initials: J
authors.lastname: Pitts-Crick
authors.forename: Tim
authors.initials: T
authors.lastname: Cripps
mesh_terms: D000328:Adult; D003452:Cryosurgery / Q000009:adverse effects* / Q000295:instrumentation*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D018570:Risk Assessment; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000209:etiology* / Q000517:prevention & control / Q000601:surgery*; D016896:Treatment Outcome