Spontaneous Echo Contrast

Spontaneous echo contrast (SEC)

Spontaneous echo contrast is often seen in left atrium in mitral stenosis. It is thought to be a fore runner of thrombus. SEC can be seen in right atrium in endomyocardial fibrosis. SEC in left ventricle is rare and can occasionally be seen in left ventricular aneurysm. SEC is also sometimes called smoke. It is seen as multiple tiny echogenic spots with a swirling movement.

Echocardiography machine settings are also important in the detection of SEC. Some machines may show a higher level of SEC while others may not. It is more commonly noted on trans esophageal echocardiography than trans thoracic echocardiography.

SEC is usually seen in low flow conditions and both erythrocytes and platelets have been related to the generation of the spontaneous ultrasonic contrast. An in vitro study showed that it is primarily due to the interaction of erythrocytes and plasma proteins at low flow and low shear rate conditions [1].

SEC in the left atrium and left atrial appendage has been associated with higher risk of thromboembolism and stroke [2]. SEC has been noted both during atrial fibrillation and sinus rhythm.

References

1. A Merino, P Hauptman, L Badimon, J J Badimon, M Cohen, V Fuster, M Goldman. Echocardiographic “Smoke” Is Produced by an Interaction of Erythrocytes and Plasma Proteins Modulated by Shear Forces. J Am Coll Cardiol. 1992 Dec;20(7):1661-8.
2. M A Siddiqui, M J Holmberg, I A Khan. Spontaneous Echo Contrast in Left Atrial Appendage During Sinus Rhythm. Tex Heart Inst J. 2001;28(4):322-3.