title: Cryoablation of typical AVNRT: Younger age and administration of bonus ablation favor long-term success.
abstract: BACKGROUND
  Cryoablation (CA) is an emerging tool for the treatment of supraventricular tachyarrhythmias. Determinants of long-term success still need clarification.
  
  
  OBJECTIVE
  The purpose of this study was to assess which patients' and procedural features affect the long-term efficacy of CA for typical atrioventricular nodal reentrant tachycardia (AVNRT).
  
  
  METHODS
  Eighty-five consecutive patients undergoing CA for typical AVNRT were divided into 3 groups of age: group A, ≤20 years, n = 20 (23.5%); group B, 21-50 years, n = 30 (35.3%); group C, ≥51 years, n = 35 (41.2%). CA was performed for 5 minutes at -75°C in all; 4-minute bonus CA was delivered if not contraindicated (ie, transient PR interval lengthening during the first application and narrow triangle of Koch). The efficacy end point was the absence of recurrences at 12-month follow-up.
  
  
  RESULTS
  CA was acutely successful in all 85 patients (100%). Bonus ablation was performed in 69 (81.2%). No permanent complications were observed. At follow-up, AVNRT recurrences occurred in 9 patients (10.6%): group A, 0 (0%); group B, 2 (6.7%), group C, 7 (20%). Incidence of recurrences was significantly different between age groups (P = .047) and between patients receiving (7.2%) and not receiving (25.0%) bonus CA (P = .038). In multivariable analysis, age groups (odds ratio [OR] 5.917; 95% confidence interval [CI] 1.372-25.518; P = .017) and bonus CA (OR 0.115; 95% CI 0.018-0.724; P = .021) were the only independent predictors of recurrences. Furthermore, age as a continuous variable remained statistically associated with recurrences (OR 1.046; 95% CI 1.002-1.091; P = .038).
  
  
  CONCLUSIONS
  CA is effective and safe for typical AVNRT ablation. Younger age and bonus CA administration are independent predictors of success at 12 months. Incidence of recurrences is low in patients younger than 21 years.
authors.affiliation: Department of Medical and Surgical Critical Care, University of Florence, Florence, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Pieragnoli
authors.affiliation: Department of Medical and Surgical Critical Care, University of Florence, Florence, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Paoletti Perini
authors.affiliation: Department of Medical and Surgical Critical Care, University of Florence, Florence, Italy. Electronic address: checchi.luca@gmail.com.
authors.forename: Luca
authors.initials: L
authors.lastname: Checchi
authors.affiliation: Department of Medical and Surgical Critical Care, University of Florence, Florence, Italy.
authors.forename: Gianmarco
authors.initials: G
authors.lastname: Carrassa
authors.affiliation: Department of Medical and Surgical Critical Care, University of Florence, Florence, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Giomi
authors.affiliation: Department of Medical and Surgical Critical Care, University of Florence, Florence, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Carrai
authors.affiliation: Department of Medical and Surgical Critical Care, University of Florence, Florence, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Michelucci
authors.affiliation: Department of Medical and Surgical Critical Care, University of Florence, Florence, Italy; Department of Cardiology, Cliniche Gavazzeni, Bergamo, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Padeletti
authors.affiliation: Department of Medical and Surgical Critical Care, University of Florence, Florence, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Ricciardi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017115:Catheter Ablation / Q000379:methods*; D003452:Cryosurgery / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012189:Retrospective Studies; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
keywords: Ablation; Age; Arrhythmias; Atrioventricular nodal reentrant tachycardia; Cryoablation; Cryotherapy; Recurrences