What is the direction of flow associated with an atrial septal defect as seen in TEE imaging?

In transesophageal echocardiography (TEE) imaging, the direction of blood flow is color-coded based on the Doppler effect. In this case, flow associated with an atrial septal defect (ASD) typically presents as blue away from the transducer and red towards the transducer.

An ASD allows blood to flow from the left atrium to the right atrium due to the pressure difference between these chambers, especially during systole when the left atrial pressure is higher. The left-to-right shunt is indicated by the red color representing the flow moving towards the ultrasound transducer. Conversely, the blue color indicates flow moving away from the transducer, which is the blood flowing from the right atrium back into the right ventricle and then towards the pulmonary arteries.

Thus, the correct interpretation of flow direction in the context of an atrial septal defect would indeed show blue away, indicating the flow away from the transducer, and red towards the transducer, indicating the left-to-right shunt direction. Understanding this will facilitate proper diagnosis and assessment of ASDs during echocardiographic evaluation.