Variable diastolic rumbling murmur caused by floating left atrial thrombus

A 53 year old man with a history of rheumatic mitral stenosis was admitted to hospital because of recurrent fainting spells. Auscultation showed a variable diastolic rumbling murmur. Simultaneous echo- and phonocardiograms demonstrated a floating left atrial thrombus; when this passed into the left ventricular inflow tract and obstructed the mitral valve orifice the diastolic murmur disappeared.