Cryoablation of typical AVNRT: Younger age and administration of bonus ablation favor long-term success

Abstract

Cryoablation (CA) is an emerging tool for the treatment of supraventricular tachyarrhythmias. Determinants of long-term success still need clarification. 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). 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. 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). 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.