Case Studies In Small Animal

Cardiovascular Medicine

Case 6

Echocardiograms and Doppler Studies

A contrast echocardiogram was performed by injecting agitated saline into a peripheral vein and watching the microbubbles traverse the heart. The microbubbles appeared in the right heart but none were seen in the left heart or aorta. Subsequently, the ultrasound transducer was placed over the caudal abdomen and the aorta identified above the bladder. Agitated saline was again injected. No microbubbles were identified in the caudal aorta but the image was not perfect and so some doubt existed as to the validity of this test. Further echocardiographic studies were then undertaken.

This echocardiogram was taken from the right side and shows a very large pulmonary artery (PA) with a structure (S) that opens into it.

When the color flow Doppler is turned on, flow through this large structure can be seen flowing from the pulmonary artery (PA) through the structure (S) into the aorta (AO). The homogeneous blue color in the structure indicates that the flow is laminar and flowing away from the transducer. When it reaches the aortic end, flow velocity exceeds the Nyquist limit (0.34 meters/second on the color bar to the left in this case) and turns gold.

A pulsed wave Doppler cursor has been placed within the structure. Flow velocity in the structure is very low but peaks in systole, flowing away from the transducer (below the line) and from the pulmonary artery toward the aorta. Some diastolic flow can also be appreciated but it is very low velocity.

©Mark D. Kittleson, D.V.M., Ph.D. All rights reserved.