[Diagnosis of atrial septum defects by M-mode echocardiography (author's transl)].

By means of M-Mode echocardiography it is possible to depict the interatrial septum, which is of importance for the diagnosis of certain congenital cardiac defects such as atrial septum defect. The echo of the interatrial septum moves in the shape of a wave, synchronous with the heart beat and shows an amplitude of about 10 mm. A dilatation of the right atrium makes the echo move dorsally, a left atrial dilatation makes the echo move closer to that of the anterior thoracic wall. If the sound beam crosses an atrial septum defect, there is a complete disappearance of echo in the region of the interatrial septum.