Distal type of nodo-ventricular pathway: Unique electrophysiological characteristics mimicking fasciculo-ventricular pathway.

Fasciculo-ventricular and nodo-ventricular pathways (FVP and NVP) are rare preexcitation variants. Normally, NVP is electrophysiologically different from FVP. We describe a unique type of NVP emerging from the distal part of the slow pathway, designated as "distal type" NVP. The distal type NVP resembled FVP but was proven by unexpected elimination of the NVP during the slow pathway ablation. Also, NVP was distinguishable from FVP by a careful comparison of the HV intervals during conduction over the fast and slow pathways. Demonstration of this novel type NVP provides insights into how the insertion site of NVP affects its electrophysiologic behaviors.