Hypercoagulability in the left atrium: Part I: Echocardiography

Abstract

Approximately 15% of patients with mitral valve disease will experience left atrial thrombosis and its consequences. The etiology and diagnosis of left atrial thrombosis are reviewed, stressing the importance of blood stagnation as the most important etiologic factor. Atrial fibrillation, a left atrial diameter greater than 60 mm and absence of significant mitral regurgitation are predictors of left atrial thrombosis in mitral stenosis. Left atrial thrombus can be detected in 50% of patients with all three factors; all influence blood stagnation. Smoke-like echoes in the left atrium, detected by echocardiography, provide a semi-quantitative assessment of left atrial blood stagnation. The incidence of thrombi in patients with well marked smoke-like echoes is 60%, while in those without this echocardiographic finding it is only 9%. Smoke-like echoes provide an early warning system of conditions in the left atrium likely to lead to thrombosis unless the patient is anticoagulated.