Cor triatriatum dexter versus prominent eustachian valve in an adult congenital heart disease patient

Abstract

An eustachian valve (EV) remnant, if present, is usually noted by the presence of a thin ridge or a crescent-shapedfold of endocardium arising from the anterior rim of the inferior vena cava orifice due to the persistence of the rightsinus venosus valve. Though the embryologic explanation of cor triatriatum dexter (CTD) is the same as that of thenormal formation of the EV—lack of regression of the right sinus venosus valve—it is usually called CTD or dividedright atrium when there are attachments on the atrial septum giving the appearance of a divided atrium. However,it’s called prominent eustachian valve when the right sinus venosus valve has partly regressed, with no remainingseptal attachments and without the appearance of a divided atrium. We present the case of an adult patient with anatrial septal defect with a high insertion of a giant EV, which mimics the echocardiographic appearance of dividedright atrium.