[Anatomopathologic-embryologic correlation in atrioventricular connection absence]

In order to offer a pathogenetic explanation for the absence of atrioventricular connexion, a correlation was made between the pathologic anatomy of this cardiac malformation and the embryonic processes which take part in the septation of the atrioventricular canal and the development of atrioventricular connections. The correspondence was made between the development of the canal's atrioventricular cushions, the septation of the common atrioventricular canal, the right and left atrioventricular canals and the morphogenesis of the mitral valve, all these processes were correlated with the anatomic elements derived from them. This led to infer that the malposition of the atrioventricular cushions divide the common atrioventricular canal unequally, giving rise to a narrow canal becoming atretic and a big canal where the mitral valve is evolved. The extreme lateralization of the atrioventricular septum to the right side would led to the absence of the right atrioventricular connection and the same process but to the left side, would give rise to the left absence of the atrioventricular connection. This ectopic septation process is supported by similar ones which can occur in other segments of the heart such as in tetralogy of Fallot and the transposition of the great arteries. This hypothesis explains sufficiently the pathologic anatomy of this type of congenital heart disease.