Transient total occlusion of the mitral valve orifice by a free-floating left atrial ball thrombus.

In patients with mitral stenosis (MS), a free-floating ball thrombus in the left atrium (LA) is a very rare clinical manifestation, but has potentially catastrophic consequences such as fatal systemic emboli or total obstruction of the narrowed mitral valve orifice, often resulting in sudden death. In this report, we demonstrated a free-floating ball thrombus within the LA cavity and transient complete occlusion of blood flow through the stenotic mitral valve by transthoracic echocardiography. Awareness of the possibility of such an entity, early diagnosis and treatment may prevent significant morbidity and mortality.