Right atrial thrombus simulating myxoma on M-mode echocardiography in a patient with pulmonary emboli

Echoes from a right atrial mass in a patient with pulmonary embolism simulated a typical echocardiographic appearance of a right atrial myxoma. The patient was admitted with recurrent pulmonary emboli and had evidence of deep venous thrombosis on venography. M-mode echocardiography showed the appearance of a right atrial mass and right atrial angiography confirmed the presence of a mass prolapsing from right atrium into right ventricle. Subsequent 2-dimensional echocardiography and careful repeat M-mode echocardiography failed to demonstrate the mass suggesting embolisation to the lungs or lysis of the thrombus.