Spontaneous contrast on echocardiography is associated with which of the following?

• A. embolic complications
• B. increased risk of LA thrombus formation
• C. no relation to LA thrombus
• D. decreased risk of embolism

Answer: (B)

Spontaneous echo contrast, the smoke-like swirling in the left atrium on echocardiography, shows that blood flow is very slow and the chamber is prone to stasis. When flow is sluggish, red cells tend to aggregate and create these echogenic patterns, signaling a prothrombotic environment. This is commonly seen with atrial fibrillation or a dilated left atrium and valvular disease, where the risk of thrombus formation in the left atrium increases. Therefore, the presence of spontaneous contrast is best interpreted as indicating a higher likelihood of developing a left atrial thrombus. It’s a marker of risk rather than a direct measure of an embolic event, though a thrombus that forms can embolize.