Background: A free-floating ball thrombus in the left atrium (LA) is very rare, but it has been associated with significant mortality and morbidity. Total obstruction of the narrowed mitral valve orifice and systemic emboli may cause syncope and sudden death.
Case Report: A 32-year-old woman with rheumatic valve disease (severe mitral and tricuspid stenosis and mild mix aortic valve disease) and acute myocardial infarction was admitted after suffering cardiac arrest. The electrocardiogram showed ST-segment elevation in leads I, II, III, aVR, aVF and V3-V6 as well as ST depression in leads aVL, V1 and V2, indicating a recent
myocardial infarct. Echocardiography revealed rheumatic, thickened, and stenotic mitral, tricuspid and aortic valves, and free-floating ball thrombi (3.5 x 3.2 cm) were detected in the left atrium. In addition, all left ventricular walls were hypokinetic (left ventricular ejection fraction (LVEF) 30 %). The patient died suddenly the next day, probably due to mitral inflow obstruction by the free-floating ball thrombi or complications of acute myocardial infarction.
Conclusions: Patients with free-floating thrombi in the LA must undergo surgery because of lifethreatening complications such as acute coronary syndrome, ischemic stroke, arrhythmias and sudden death.

Keywords: Mitral Valve Stenosis