[Echocardiographic features of the eustachian valve and its clinical significance (author's transl)].

The detailed informations and clinical significance of the Eustachian valve have not yet been elucidated. Real-time two-dimensional echocardiography has enabled one to investigate the Eustachian valve non-invasively. The valve was usually very small. The larger valve was a few cm in length and moved with heart beat. Its motion was analyzed with M-mode echocardiography. In the cases with sinus rhythm, the valve opened gradually in systole, and opened further in rapid filling phase,. followed by the rapid closing at the time of atrial contraction. In the cases of atrial fibrillation with severe tricuspid regurgitation, the valve remained at the semi-closed position throughout systole and opened in rapid filling phase. In one case of tricuspid regurgitation the valve was observed to flutter in systole. After the surgical repair of the tricuspid valve, systolic opening of the valve was noted, though atrial fibrillation persisted.