Syncope induced by transient total occlusion of the mitral valve orifice by a giant free-floating left atrial thrombus.

Left atrial ball thrombus is a rare disorder with potential fatal systemic embolism or mitral valve orifice occlusion that may result in sudden death. Its treatment is still controversial and is often associated with poor prognosis. We report the case of a 95-year-old woman with a history of permanent atrial fibrillation who was admitted to our hospital for syncope.