ABSTRACT
To demonstrate that the right ventricular infundibulum changes its spatial orientation in hearts with complete transposition of the great arteries, sixty five hearts with this malformation, with anterior and right sided aorta were studied morphometrically. The inlet apex and infundibular arises in the right ventricule were interrelated. The angles formed by the intersection of both arises were measured, and the results were compared with those obtained from a similar study in thirty five normal hearts. The angles obtained in the hearts with transposition of the great arteries were of 156.5 degrees, and those measured in the normal hearts were of 126.6 degrees. This difference was interpreted as an indicator of a vertical shift of the right ventricular infundibulum toward the right, to the same side in which the aorta is located and with which it is connected. In this way this outlet looses its leftward direction observed in normal hearts. It is concluded that although complete transpositions of the great arteries developmentally has its origin primarily in the truncus of the embryonic heart, the infundibulum is also involved modifying its position.