Echocardiographic analysis of intracardiac anatomy in endocardial cushion defect.

A standard echocardiographic technique was proposed for an analysis of the intracardiac anatomy of endocardial cushion defect (ECD). It consisted of two beam directions, mitral and tricuspid, and two M-mode scans, between the mitral and tricuspid valves and between the mitral and aortic valves. Using this technique, echocardiographic studies were performed on 13 patients with ECD, including 10 patients with the incomplete form and three patients with the free-floating form. In patients with the incomplete form, an M-mode scan between the mitral and tricuspid valves showed the specific features of the interaction between the mitral valve, the interventricular septum, and the tricuspid valve, termed the "mitral-interventricular septal-tricuspid (MVT) connection." The systolic multiple echoes and the diastolic echoes of the so-called posterior leaflet of the mitral valve were constant findings in the mitral direction. The tricuspid valve, although less continuous, was recorded simultaneously with the mitral valve in the same direction. Ateriorly displacement of the anterior mitral leaflet was shown on an M-mode scan between the mitral and aortic valves, giving an echocardiographic representation of the angiocardiographic "goose-neck" sign. Evidence showing the presence of right ventricular volume overload was also found. In patients with the free-floating form, an anterior common A-V valve with a large excursion was recorded on an M-mode scan between the mitral and tricuspid valves. The valve was located posterior to the interventricular septum in the mitral direction and anterior to the septum in the tricuspid direction. There was no finding to show the interaction between the valve and the septum. The posterior common A-V valve was registered only in the mitral direction. Our technique made it possible to diagnose ECD, using a noninvasive echocardiographic method, and discriminate the free-floating form from other forms of ECD.