[Tetralogy of Fallot: considerations about morphologic features of a well described entity]

To analyze some morphological aspects of the tetralogy of Fallot which have been raising controversies in the literature, due to the different approach to the nomenclature of congenital heart defects by different authors regarding the definition of double outlet right ventricle and its concomitance with tetralogy.

We reviewed the original description of the anomaly, and also analyzed the morphology of 22 anatomical specimens, describing the degree of aortic overriding, the type of ventricular septal defect, the degree of sub-pulmonary stenosis, etc.

Regarding the degree of aortic overriding, there was only one case where that vessel connected predominantly to the left ventricle. In the remaining hearts, the degree of overriding was between 50% and 75% in 10 cases and greater than 75% in 11. The intensity of infundibular stenosis was evaluated as mild in half the available hearts, and the pulmonary valve was bicuspid in 11 cases. Right aortic arch was present in 40% of the available hearts and the ventricular septal defect had muscular borders in just one case (5%).

We could conclude that if double outlet is only a type of ventricle-arterial connexion, and so, depending on the degree of overriding of the aorta over the trabecular septum, we may have the malformation coexisting with the tetralogy.