Case 9 — Doppler

Continuous wave Doppler tracing recorded from the left apex across the mitral regurgitation jet. Peak systolic velocity is 4.50 m/s. The modified Bernoulli equation calculates a pressure gradient (PG) of 81 mmHg across the mitral valve in systole. Systemic systolic arterial blood pressure measured with a Park's Doppler unit was 125 mmHg.
CW Doppler across the mitral regurgitation jet (left apex). Peak systolic velocity: 4.50 m/s; calculated pressure gradient: 81 mmHg. Systemic systolic BP (Park’s Doppler): 125 mmHg.

The left ventricular pressure was 81 mmHg higher than the left atrial pressure. Since peak systolic left ventricular pressure and peak systolic systemic arterial blood pressure should be almost the same (no evidence of aortic stenosis), Bingo’s systemic systolic BP of 125 mmHg can be used to estimate left atrial pressure.

Quiz

1. What is this dog’s estimated peak systolic left atrial pressure based on the spectral Doppler findings?

2. Normal left atrial pressure is <10 mmHg. What will the left atrial pressure in this dog produce?

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