[Association of nodoventricular and atrioventricular fibers with the origin of reciprocating tachycardia. Electrophysiological and anatomopathological aspect].

A 25 year old patient presented with several types of paroxysmal tachycardia. Analysis of the recordings and the results of endocavitary electrophysiological investigation suggest the presence of nodoventricular and atrio-ventricular fibres. These two accessory pathways were latent in sinus rhythm but formed part of reentry loops. The reciprocating rhythms used the Kent bundle in the retrograde direction, and either the normal nodo-hisian or the Mahaim fibres in the anterograde direction. Simple echos ascending by the nodo-hisian pathway and descending by the nodo-ventricular pathway were also observed. The patient died of an unassociated cause and a pathological examination of the heart was performed. This confirmed the presence of a left posterior paraseptal Kent bundle and the presence of fibres relaying the inferior part of the atrioventricular node to the septal ventricular myocardium, this being made possible by a dehiscence of the central fibrous body.