[Double outlet right ventricle. Embryological approach]

It is proposed a pathogenetic explanation that explains the morphogenesis of the anatomic variants of double outlet right ventricle.

An anatomic embryological correlation was made in which the plane separating the outlets and great arteries in the types of this cardiopathy was compared with the normal truncoconal septum in the embryonic heart. Thirty five hearts with double outlet right ventricle were described, fifteen with great arteries slightly crossed, ten with side by side great arteries and ten with anterior aorta and posterior pulmonary artery. The cephalic border of the truncoconal septum was compared with its inferior border in each group. With this procedure we calculated the type of torsion of the truncoconal septum.

In the slightly crossed great arteries the truncoconal twist was of 135° in side by side great arteries the twist was of 90° and in anterior right aorta the truncoconal septum was straight with 0° of rotation, and with left anterior aorta the rotation was of -90°.

Embryologically double outlet right ventricle is originated by the persisting continuity between the right ventricle with the truncus and conus which form the great arteries and their outlets. The anatomic variations are the consequence of progressive detortion of the truncoconal septum followed by a torsion of -90°.