RESUMEN
The Eustachian valve (EV) is an embryonic remnant of the valve of the inferior vena cava (IVC). In some cases, the EV can be prominent and presenting as a thin, elongated and ecodense membrane, superimposed to the septal aspect of the RA, below the fossaovalis, partially dividing the RA in two chambers. Echocardiography is the method of choice for the diagnosis of this finding. The correct identification of this anatomic variant is very important for the differential diagnosis of the masses and tumors in the RA. Inpatients referred for cardiac surgery, as in the closure of atrial septal defects (ASD), it is fundamental the identification of this structureto avoid complications as the inadvertent closure of an EV considered as part of the atrial septum. The finding of a redundant EV can also add technical difficulties for the percutaneous treatment of ASD. The correct recognition and detailed description of this finding are important to avoid equivocal diagnosis and complications in patients referred for cardiac surgery. Thus, attention to this anatomicvariant, and careful TEE examination are fundamental for the correct diagnosis and therapeutic approach.