Auscultatory and echocardiographic features of mobile left atrial thrombus.

Free floating ball thrombus of the heart is a rare disorder that usually involves the left atrium, particularly in association with mitral stenosis and atrial fibrillation. The diagnosis of ball thrombus is suspected clinically when there are auscultatory changes in the intensity of the murmur of mitral stenosis. Two-dimensional echocardiography is especially useful in the diagnosis of this condition. By combining phonocardiographic recordings with both M-mode and two-dimensional echocardiography, attenuation and disappearance of the murmur were demonstrated as the mobile thrombus randomly drifted into the mitral valve orifice. Reappearance of the cardiac murmur was noted as the thrombus was expelled from the orifice. This study, combining simultaneous phonocardiography and two-dimensional echocardiography, identifies for the first time the relation between thrombus movement into the mitral aperture and changes of the murmur of mitral stenosis.