Supraventricular tachycardia and aberration of the cardiac conduction system.

A case of a baby with supraventricular tachycardia who died is reported. Histological examination of the cardiac conduction system revealed a hypoplastic sinus node and an unusual connexion between the branching bundle and the atrioventricular node. There was no electrocardiographic evidence to suggest that the anomalous pathway functioned; the unusual configuration was probably within the normal range of morphological variations.