The modified Bernoulli equation can be use to translate blood velocities into transvalvular pressure gradients:
P = 4 x V2
Where V is the velocity of flow across the valve or vessel and P is the pressure gradient (in mmHg). This is used to classify the severity of stenosis (e.g. pulmonic stenosis or subaortic stenosis), and in the assessment of pressure gradients in valvular insufficiency or shunts.
V (m/s) =
P (mmHg) =