title: Cryoablation of atrioventricular nodal re-entrant tachycardia: 7-year follow-up in 515 patients-confirmed safety but very late recurrences occur.
abstract: OBJECTIVE
  Cryoablation is an alternative method to radiofrequency ablation for treatment of atrioventricular nodal re-entrant tachycardia (AVNRT). This study investigates the long-term safety and efficacy of cryoablation in AVNRT.
  
  
  RESULTS
  We studied 515 consecutive patients (317 women, mean age 50 years, range 13-89 years) undergoing a first cryoablation for AVNRT between 2003 and 2008. Ablations were performed with a 6-mm Freezor Xtra catheter. Six patients were acute failures; 494 out of 509 (97%) primarily successfully ablated patients were followed up for a mean of 7.1 years (range 2-12 years). About 11% (54/494 patients) of patients had recurrences of the index arrhythmia. Time to recurrence varied from days to 9 years; 14 patients (3%) had recurrences later than 2 years, 8 patients (2%) later than 3 years, and 6 patients (2%) later than 4 years. Recurrence rate was higher in patients with slow-slow or fast-slow AVNRT (n = 24) compared with the common slow-fast variant (25 vs. 10%; P = 0.04). Recurrence rate was not higher in patients with residual slow pathway conduction (jump with or without echo beat, n = 199, 39%). Transient atrioventricular (AV) block of the first-, second-, or third-degree during ablation was observed in 45 patients but had no impact on the risk of AVNRT recurrence. No late AV block occurred. Single vs. multiple applications or total amount of cryoenergy delivered did not differ between patients with and without recurrences.
  
  
  CONCLUSIONS
  Cryoablation in AVNRT is safe with a long-term efficacy of 88%; however, very late recurrences occur.
authors.forename: Per
authors.initials: P
authors.lastname: Insulander
authors.forename: Hamid
authors.initials: H
authors.lastname: Bastani
authors.forename: Frieder
authors.initials: F
authors.lastname: Braunschweig
authors.forename: Nikola
authors.initials: N
authors.lastname: Drca
authors.forename: Göran
authors.initials: G
authors.lastname: Kennebäck
authors.forename: Jonas
authors.initials: J
authors.lastname: Schwieler
authors.forename: Jari
authors.initials: J
authors.lastname: Tapanainen
authors.forename: Mats
authors.initials: M
authors.lastname: Jensen-Urstad
mesh_terms: D000200:Action Potentials; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D054537:Atrioventricular Block / Q000209:etiology; D002648:Child; D003452:Cryosurgery / Q000009:adverse effects; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012307:Risk Factors; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
keywords: Atrioventricular block; Atrioventricular node re-entrant tachycardia; Cryoablation; Long-term follow-up