Tricuspid atresia. Microscopic findings in relation to "absence" of the atrioventricular connexion.
In 10 out of 31 cases of tricuspid atresia (absent atrioventricular connexion), gross examination of the morphologically right ventricle suggested the presence of a tiny inlet portion in addition to the trabecular portion. Serial sections of two of these hearts have proven this diagnosis: a fibrous remnant in continuity with the central fibrous body was present not only above the left ventricle but also above the right ventricle. We interpreted this as a remnant of the atrioventricular valve and we also observed that the ventricle had a hypoplastic inlet portion. This inlet portion was bounded by a microscopically small septomarginal trabeculation containing the right bundle branch. Therefore, the diagnosis of absent connexion, which after clinical or gross anatomical investigation remains an appropriate one, cannot always be maintained after microscopical study if it is considered that the fibrous remnant represents evidence of a connexion initially present between the right ventricle and the right atrium.
D006325:Heart Atria / Q000473:pathology; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D014261:Tricuspid Valve / Q000002:abnormalities* / Q000473:pathology