Conduction Properties and Ablation of Adenosine Sensitive Accessory Pathways in Children

Block in accessory pathway (AP) conduction with adenosine has been previously described. However, conduction characteristics of these APs has not been well defined to date. All patients with APs </ = 21 years old who underwent an EP study from 2014 to 2017 were included in our study. Patients with adenosine sensitive APs were identified (group 1). Demographic and AP conduction characteristics were compared between group 1 and the entire cohort of patients. Local atrioventricular (AV) or ventriculoatrial (VA) time, cycle length and need for isoproterenol were compared to a control group matched by age and AP location (group 2). Student’s t test, Wilcoxon rank sum, χ² and Fisher’s exact were used for analysis. Fourteen (7%) out of 207 patients had an adenosine sensitive AP. The median age of patients with adenosine sensitive APs was 11.8 (IQR 8.5–13.5) years vs. 14 (IQR 10.6–16.7) for the rest of the cohort (p = 0.04). Three of the 134 patients with preexcitation had adenosine sensitive APs (2%) vs. 11 of the 73 patients with concealed APs (15%) (p = 0.001). The median local AV/VA time at the site of successful ablation was longer in group 1 vs group 2 [78 ms, IQR 62–116 vs. 31 ms, IQR 30–38; p < 0.001]. Antegrade AP effective refractory period and total procedure time were longer in patients with adenosine sensitive APs (p = 0.03 & p = 0.04, respectively). Adenosine sensitive APs which occur in children are more often concealed. These APs have a longer conduction time at the site of successful ablation.