Successful emergency percutaneous balloon mitral valvotomy in a patient with massive left atrial thrombosis: utility of transesophageal echocardiographic monitoring.

Emergency percutaneous balloon mitral valvotomy was carried out successfully in a 65-year-old woman with severe mitral stenosis and massive left atrial thrombosis. Transesophageal echocardiography was of great value in monitoring each step of the procedure in order to avoid systemic embolization due to improper manipulation of the dilating apparatus within the left atrium.