Abstract
The observation that subpulmonary or doubly committed subarterial ventricular septal defects occur with a high frequency among orientals as compared to westerners has led to the hypothesis that a racial difference exists with regard to normal and abnormal development of the embryonic conal septum.
In an attempt to contribute to this concept we have studied 24 normal hearts and 70 hearts with a perimembranous ventricular septal defect from patients of Japanese and Dutch origin. The length of the infundibular septum and the length of the right ventricle were not statistically different between the 2 groups.
These findings suggest that in normal hearts and in hearts with perimembranous ventricular septal defects no racial differences exist with respect to the role of the embryonic tonal septum in contributing to the definitive infundibular septum. The results indicate that subpulmonary or doubly committed subarterial defects may have a different origin from that of the usual perimembranous defect.
