A restrictive atrial septal defect is a risk factor for mortality in some forms of left heart disease, and can be predicted from the patterns of flow in the pulmonary veins in fetal life. Our objective was to document the patterns of pulmonary venous flow of blood in different forms of left heart disease in the fetus. The pulmonary venous flow profile was documented in 61 cases. The systolic, diastolic, and reverse waves were measured and compared to normal. Profiles of venous flow suggestive of restriction at the atrial septum were found in 32 of 61 cases using the ratio of systolic to diastolic waves, and 26 cases using the height of the reverse wave.

A restrictive atrial septal defect was found most commonly in fetuses with critical aortic stenosis or the hypoplastic left heart syndrome, and was less frequently seen in the setting of mitral atresia or coarctation. In order to plan appropriate postnatal management, examination of the profiles of pulmonary venous flow is an essential part of the evaluation of any form of left heart disease detected in the fetus.