Syncope Due to a Free-floating Left Atrial Thrombus.

A 74-year-old woman with nonvalvular chronic atrial fibrillation was admitted for pre-syncope. She fainted and developed acute arterial occlusion after one month of admission. Echocardiogram showed a 2.6×2.8-cm free-floating ball thrombus in the left atrium (LA) that had not been documented at the initial admission. Its left lateral decubitus position caused left ventricular (LV) inflow obstruction during the diastolic phase (Picture A); the obstruction was released during the systolic phase (Picture B). Transesophageal echocardiogram confirmed the giant thrombus in the LA (Picture C). As an LA thrombus can be associated with serious outcomes (1), it was emergently resected and pathologically confirmed as a relatively new, nonpedunculated, fibrin thrombus (Picture D and E). A free-floating LA ball thrombus without mitral stenosis is rare with anticoagulation therapy (2). In our case, dehydration, temporarily insufficient warfarin control due to loss of appetite, and a dilated LA may have caused thrombus formation.

Picture.

The authors state that they have no Conflict of Interest (COI).