Hypoplasia of the lung and heart in fetal rats with diaphragmatic hernia.

We studied 11 fetal rats with normal heart and diaphragmatic hernia induced by administration of bis-diamine (200 mg) on the 9th and 10th day of pregnancy. After rapid whole-body freezing on the 21st day, the fetuses were studied by means of serial cross-sectional photographs of the frozen thorax. In the fetuses with hernia, the left half of the diaphragm was completely absent, and the liver and stomach were in the left hemithorax. The lung and heart were hypoplastic in fetal diaphragmatic hernia. Cardiac volume reduction involved all four chambers and was more prominent in the left atrium and ventricles. The great vessels were also smaller.