Preexcitation secondary to fasciculoventricular pathways in children: A report of three cases

Introduction: Fesiculoventricular connections are the rarest form of access ory pathways leading to preexcitation, Electrophysiologic characteristics o f these pathways include ventricular preexcitation with normal PR and AB in tervals and short HV intervals during sinus rhythm. In addition, atrial ove rdrive pacing prolongs the PR interval without affecting the HV interval or the degree of preexcitation. Methods and Results: From March 1994 through February 1997, 3 of 59 pediatr ic patients referred far electrophysiologic study for preexcitation on surf ace ECGs were found to have fasciculoventricular pathways. Two patients had no inducible supraventricular tachycardia, One patient had successful abla tion of both a left lateral pathway and a concealed anterolateral pathway t hat had facilitated antidromic and orthodromic supraventricular tachycardia s, respectively. Conclusion: Children often manifest minimal preexcitation via accessory AV pathways due to rapid AV conduction and/or left lateral pathway location. F asciculoventricular pathways may masquerade as Wolff-Parkinson-White syndro me. Separation of the two diagnoses depends on the demonstration of specifi c electrophysiologic criteria.