Morphometric study of right ventricle in 32 cases of tetralogy of Fallot

The right ventricle was the object of a morphometric study in a total of 32 human hearts with tetralogy of Fallot. Most subjects died in the perinatal period and weighed between 720 and 5,000 g. Nine internal parameters were measured in each right ventricle and substituted into the appropriate stereometric formula to yield volumes for each right ventricular chamber. The data obtained were compared to patterns of normality previously obtained by mathematical analysis. The results can be summarized as follows: 1. The right ventricular wall in the present series was thicker than normal, particularly near the tricuspid valve annulus. 2. Pulmonary valve and pulmonary infundibulum perimeter were below normal. 3. Tricuspid valve perimeter was above normal. 4. Above normal figures were obtained for length and volume of the right ventricular inflow tract. 5. Increased outflow tract length contrasted with below normal figures for outflow tract volume. 6. In a large number of cases (95%) the distance between the crista supraventricularis and the pulmonary sigmoid leaflets was reduced. Characterization of these changes may help to elucidate the embryological origin of tetralogy of Fallot.