Observations on the Interatrial Pressure Gradients in Man

It was possible to calculate pressure gradients across the interatrial septum in several cases of congenital heart disease. Gradients in cases of interatrial septal defect are similar to those found in animals with artificially produced defects. The data are used to form a rounded picture of the hemodynamics of interatrial septal defect. In pulmonic stenosis with interatrial communication, reversal of the usual left-to-right gradient may occur only during atrial systole. Under these circumstances it is often possible to distinguish a patent foramen ovale with competent valve from an interatrial septal defect.