Abstract 13142: Characteristics of Decremental Accessory Pathways in Children

Abstract

Introduction: While decremental retrograde accessory pathways (DAPs) classically present clinically as permanent junctional reciprocating tachycardia (PJRT), they may be diagnosed unexpectedly during electrophysiology study (EPS). Although DAPs associated with PJRT have been studied, information about other variants of DAPs in children is limited. Methods: We retrospectively studied patients 0 - 21 years of age with retrograde DAPs who underwent EPS between 2005 and 2014. Decrement was defined as rate-dependent prolongation of the local ventriculo-atrial (VA) time by > 30 ms during ventricular extrastimulus or rapid ventricular pacing. Clinical presentation, electrophysiologic properties and ablation outcomes of patients with DAPs were compared to an age-matched cohort of patients with non-decremental accessory pathways. In addition, a sub-analysis examined patients with DAPs depending on whether clinical PJRT was diagnosed prior to the EPS. Results: A total of 29 patients with DAPs and 83 controls were included [mean age at time of EPS 10.3 ± 5.7 years and 10.7 ± 5.2 years, respectively (p = NS)]. Compared to controls, DAPs were more likely to be associated with syncope [6/29 (21%) vs 3/83 (4%), p = 0.01], ventricular dysfunction [6/29 (21%) vs 4/83 (5%), p = 0.04], and treatment with antiarrhythmic medications [20/29 (69%) vs 39/83 (47%) p = 0.04]. In addition, DAPs were more likely to be right-sided [20/29 (69%) vs. 24/83 (29%), p < 0.01] and septal [19/29 (66%) vs 17/83 (21%), p < 0.01]. DAPs and their age-matched controls had similar rates of acute ablation success [26/29 (90%) vs 77/83 (93%), p = NS] and recurrence [2/29 (7%) vs 4/83 (5%), p = NS]. There were no major procedural complications in either group. Of the patients with DAPs, only 12 (41%) had clinical PJRT, and these patients had more syncope [6/12 (50%) vs 0/17 (0%), p < 0.01], slower ORT (mean cycle length 383 ± 89 ms vs 323 ± 60 ms, p = 0.04), and longer maximum VA times (mean 283 ± 116 ms vs 208 ± 42 ms, p = 0.01) compared to those with DAPs without clinical PJRT. Conclusions: The majority of pediatric patients with DAPs do not present with clinical PJRT. DAPs in general are typically associated with more severe symptoms, but ablation outcomes are similar to age-matched controls with non-decremental pathways.