We herein report a woman in her 70s was admitted to hospital with
myocardial and multiple lacunar cerebral infarction, transthoracic
echocardiogram revealed an active thrombus in the left atrium like a
ping-pong ball. Anticoagulation was administered with low molecular
weight heparin but did not work, the patient later developed cerebral
infarction in the right frontotemporal lobe. There is a greater risk of
severe cerebral infarction in active left atrial thrombus without mitral
stenosis. Echocardiography played an important role in definitive
diagnosis.