[Two-dimensional echocardiographic observation of a rapidly growing floating left atrial ball thrombus: report of a case with mitral stenosis].

This report dealt with a rapidly growing ball thrombus floating in the left atrium in a case with mitral stenosis detected by serial two-dimensional echocardiography and confirmed at operation. A 45-year-old female was admitted to our hospital on January 7, 1982 because of dyspnea, orthopnea and fever. On admission she had typical auscultatory signs of mitral stenosis, and her chest roentgenogram revealed slight pulmonary venous congestion and marked left atrial enlargement. Laboratory findings including complete blood counts, coagulation studies and blood chemistry were normal except a positive CRP test. Two-dimensional echocardiography performed on January 8 revealed a tight mitral stenosis with the mitral orifice area of about 0.9 cm2, and a floating ball thrombus in the left atrium, which was 2.5 X 3 cm in size. Fuzzy echoes flowing slowly around the thrombus were also observed. Intravenous administration of heparin was started immediately. In the next morning (January 9), the two-dimensional echocardiography was reexamined, which revealed a markedly growing thrombus which became 4 X 4 cm in size. Several hours after the reexamination mitral valve replacement was performed. The removed thrombus was 5.5 X 7 cm in size and consisted of three laminated structures. This finding was consistent with the echocardiographic observations. Coagulation studies made just before operation showed increased coagulability. Increased stagnation of blood in the left atrium due to heart failure and a transient increase of blood cell aggregation and coagulability induced by preceding infection might be responsible for the genesis of such a thrombus.