The effect of body position on a free-floating ball thrombus as observed by transesophageal echocardiography.

Two cases of free-floating left atrial ball thrombi (FLABT) in association with mitral stenosis were observed by transesophageal echocardiography (TEE). Our report describes the relation between body position and thrombi kinetics. Both cases demonstrated similar kinetics. In the supine and right lateral decubitus positions, the thrombi recoiled from and sometimes became entrapped within the mitral valve. In the sitting and left lateral decubitus positions, the thrombi appeared to be nearly fixed and did not contact with the mitral valve. Our results indicate that the latter two positions prevent thrombi disintegration and incarceration into the mitral valve. Finally, TEE is an extremely useful tool for assessing the safest position for individuals with FLABT.