inserts into the lower portion of the interatrial septum adjacent to the atrioventricular valves. However, higher insertion of a giant eustachian valve, which mimics the echocardiographic appearance of divided right atrium, is very rare. This type of abnormality may be confused with cor triatriatum dexter. Very rarely, such a configuration of a large eustachian valve may mimic a right atrial cystic tumor. The superior vena cava (SVC) does not have any homologous valve or valvule. Clinical significance The eustachian valve is frequently seen with transthoracic echocardiography from the parasternal long axis, the apical four-chamber and the sub-costal four-chamber views. The eustachian valve is better seen with transesophageal echocardiography in the bi-caval view and right sided horizontal and longitudinal views. Association between the eustachian valve and patent foramen ovale has been studied in patients with cryptogenic stroke (stroke of unknown cause). History The eustachian valve, also called valvula venae cavae inferioris, was described for the first time by the Italian anatomist Bartolomeo Eustachi (born between 1500 and 1513, died 1574). References External links - "Right atrium, internal structure, anterior view" Cardiac anatomy