Utility of postural change in differentiating sludge from thrombus in the left atrial appendage: A case report.

We detected symptomatic atrial fibrillation in a 64-year-old man who had undergone mitral valvuloplasty. While performing transesophageal echocardiography (TEE) in the left lateral decubitus position, we detected an isoechoic mass lesion at the bottom of the left atrial appendage (LAA). After changing the patient's position from left to right, the mass lesion dropped down from the bottom of the LAA, spread out into the left atrium, and appeared as a spontaneous echocardiographic contrast with mobility. We therefore diagnosed the mass lesion as not a thrombus but sludge. Changing the patient's position during TEE is useful for distinguishing sludge from thrombi.