Case 11 — Continuous Wave Doppler

Continuous wave Doppler velocity tracing of the systolic MR jet in the left atrium showing a pressure gradient across the mitral valve of 115 mmHg. Systemic systolic arterial BP was approximately 170 mmHg.
CW Doppler of the MR jet. Pressure gradient across the mitral valve: 115 mmHg. Systemic systolic BP: ~170 mmHg.
Continuous wave Doppler beam placed in the blood flow jet flowing from the left atrium to the right atrium through the atrial septal defect. The pressure gradient across the interatrial septum is 47 mmHg.
CW Doppler across the atrial septal defect (LA to RA). Pressure gradient: 47 mmHg. Since the dog is in right heart failure, RA pressure must be 10–15 mmHg.
Continuous wave Doppler measuring the velocity of the tricuspid regurgitation jet in systole. The peak pressure gradient is approximately 52 mmHg.
CW Doppler of the tricuspid regurgitation jet. Peak pressure gradient: ~52 mmHg.

Quiz

1. What is the systolic pressure in this dog’s left atrium using the MR jet velocity and the systemic systolic blood pressure as reference points?

2. Using the velocity of blood flow across the interatrial septum and an assumed right atrial pressure of 13 mmHg as reference points, what is the calculated left atrial pressure?

3. What is the rhythm disturbance that occurs on the fifth beat in the second image?

4. Based on the tricuspid regurgitant jet velocity, what is the systolic right ventricular pressure if we again assume right atrial systolic pressure is 13 mmHg?

5. Based on the answer above, if we assume the pulse pressure in the pulmonary artery is 25 mmHg, what is the pulmonary artery diastolic pressure (which should be close to the diastolic left atrial pressure)?

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