Prominent Eustachian Valve Mimicking Thrombus in Right Atrium Diagnosed with Computed Tomography in a Patient with Atrial Fibrillation

A 51-year-old man presented with paroxsysmal atrial fibrillation (AF). Transthoracic echocardiography revealed mass of 2.3x0.6 cm adjacent to the superior part of the right atrium (RA) compatible with thrombus. Although thrombus formation in the setting of AF is more common in left atrial appendage and left atrium it can also be seen in right atrial appendage and RA. We performed cardiac computerized tomography (CCT) in order to clarify the nature of mass in RA and exclude coronary stenosis. CCT showed prominent eustachian valve measuring 3.2 cm which was not clear on echocardiography. This case underscores the importance of complementary cardiovascular imaging to facilitate the correct diagnosis.