[Echocardiographic abnormalities of the mitral valve in interatrial communication of the ostium secundum type].

Thirty one patients with atrial septal defect were studied by M-mode echocardiography. In sixteen patients (control group) there only findings suggesting right ventricular volume overload. The remaining fifteen patients, were divided into three groups. Group 1 consisted of five patients with mitral valve abnormalities related to the left ventricular pattern. The macroscopic aspect of the mitral valve in this group was reported by the surgeon to be rheumatic or myxomatous degeneration. In four patients (group II), there was prolapse of an atrioventricular valve, three mitral and one tricuspid. Group III consisted of six patients with an abnormal movement of the posterior mitral leaflet, related to a deformed left ventricle. The QP/QS ratio as well as the interatrial shunt was larger in groups I and III. These data suggest that there are abnormal mitral flow patterns and changes in the left ventricular geometry, related to right ventricular volume overload that cause altered mitral valve movement that can be detected by echocardiography.