Interatrial septal thrombus-in-transit despite severe mitral regurgitation.

A 47-year-old man presented with 1-day history of dyspnoea and near syncope. Electrocardiography showed sinus rhythm and chest X-ray showed mild cardiomegaly. Serum troponin I was mildly elevated at 0.371 ug/l. Arterial blood gases showed hypoxaemia with pO2 of 55mmHg. Transthoracic echocardiography revealed dilated left atrium (LA) and severe mitral regurgitation refluxing into pulmonary veins (Figure 1B). The mitral regurgitation was secondary to a possible perforation in the prolapsed anterior mitral valve leaflet (AMVL; Figure 1A). There was a mobile echodensity across the interatrial septum (IAS; Figure 1D). Computed tomography of the pulmonary arteries revealed the presence of filling defects in branches of both the right and left pulmonary arteries, consistent with pulmonary embolism. The patient was anti-coagulated. A pre-operative transoesophageal