A 64-year-old female patient was seen in the outpatient clinic with complaints of breathlessness on exertion. She had no history of syncopal attacks. Auscultation of the heart disclosed an opening snap and a mid-diastolic murmur. Transthoracic echocardiography revealed a giant left atrial tumour measuring 9.5 × 4.0 cm (38 cm 2 ), which was attached to the fossa ovalis of the interventricular septum ( Videos 1 and 2 ). The giant mass protruded through the mitral valve in diastole, thereby obstructing blood flow to the left ventricle. Doppler signal analysis revealed normal aortic flow (1.1 m/s) and mitral flow with a flow velocity of 1.88 m/s and a mean gradient of 7.9 mmHg, mimicking moderate mitral stenosis flow obstruction due to the giant left atrial tumour. Preoperatively, the patient underwent routine coronary angiography, which demonstrated unique opacification of a vascular network from a large posterolateral branch of the right coronary artery providing blood supply to the giant tumour ( Fig. 1 ). Thereupon, the patient was operated on successfully. Histopathological examination of the resected tumour demonstrated the mass to be a myxoma cordis.
