title: Cooling dynamics: a new predictor of long-term efficacy of atrioventricular nodal reentrant tachycardia cryoablation.
abstract: OBJECTIVE
  Catheter ablation of the slow pathway is the most effective treatment for atrioventricular nodal reentrant tachycardia (AVNRT). Cryoenergy, compared to radiofrequency, relates to lower heart block risk but higher incidence of AVNRT recurrences. The aims of this study are to confirm the safety and efficacy of AVNRT cryoablation and to identify predictors of long-term recurrences.
  
  
  METHODS
  Among 241 patients undergoing AVNRT cryoablation, 239 (99.2%) experienced acute effective cryoablation of the slow pathway, and no procedure-related complications were reported.
  
  
  RESULTS
  After a follow-up of 44.9 ± 31.7 months, 28 (11.7%) patients presented AVNRT recurrences. A shorter preablation (p = 0.05) and postablation anterograde Wenckebach cycle length (p < 0.01), a shorter postablation atrioventricular node refractory period (p = 0.04), and persistence of the crossover sign (p = 0.03) were associated with higher incidence of long-term recurrences. Considering cooling dynamics, a longer time to reach temperature ≤-70 °C (p = 0.03) and a higher minimal temperature during ablation (p = 0.04) were related to recurrences. Patients without residual markers of dual AV node physiology (AH jump, single atrial echo beat, crossover) reported a lower recurrence rate (p = 0.05) compared to those without. At multivariate analysis, a longer time to -70 °C was the strongest independent predictor of long-term recurrence (OR 1.75, 95% CI 1.01-3.03, p = 0.04).
  
  
  CONCLUSIONS
  AVNRT cryoablation is safe and effective. Long-term recurrence rate was 11.7%. An ablation approach directed to the complete elimination of dual AV node physiology, along with assessment of the tissue's cooling dynamics, holds the potential to improve long-term AVNRT cryoablation efficacy.
authors.affiliation: Division of Cardiology, Department of Medical Sciences, "Città della Salute e della Scienza" Hospital, University of Turin, Corso Bramante 88, 10126, Turin, Italy. m.matta26@gmail.com.
authors.forename: Mario
authors.identifier: http://orcid.org/0000-0002-5482-0771
authors.initials: M
authors.lastname: Matta
authors.affiliation: Division of Cardiology, Department of Medical Sciences, "Città della Salute e della Scienza" Hospital, University of Turin, Corso Bramante 88, 10126, Turin, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Anselmino
authors.affiliation: Division of Cardiology, Cardinal Massaia Hospital, Asti, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Scaglione
authors.affiliation: Division of Cardiology, Department of Medical Sciences, "Città della Salute e della Scienza" Hospital, University of Turin, Corso Bramante 88, 10126, Turin, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Vitolo
authors.affiliation: Division of Cardiology, Department of Medical Sciences, "Città della Salute e della Scienza" Hospital, University of Turin, Corso Bramante 88, 10126, Turin, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Ferraris
authors.affiliation: Division of Cardiology, Cardinal Massaia Hospital, Asti, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Di Donna
authors.affiliation: Division of Cardiology, Cardinal Massaia Hospital, Asti, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Caponi
authors.affiliation: Division of Cardiology, Department of Medical Sciences, "Città della Salute e della Scienza" Hospital, University of Turin, Corso Bramante 88, 10126, Turin, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Castagno
authors.affiliation: Division of Cardiology, Department of Medical Sciences, "Città della Salute e della Scienza" Hospital, University of Turin, Corso Bramante 88, 10126, Turin, Italy.
authors.forename: Fiorenzo
authors.initials: F
authors.lastname: Gaita
mesh_terms: D003452:Cryosurgery / Q000379:methods / Q000706:statistics & numerical data*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology* / Q000517:prevention & control*; D015995:Prevalence; D011379:Prognosis; D012008:Recurrence; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000453:epidemiology* / Q000601:surgery*; D016896:Treatment Outcome
keywords: AVNRT; Cooling dynamics; Cryoablation; Slow pathway; Supraventricular tachycardia