LAPms= Systolic radial artery pressure (cuff) - DP = 125 - 117= 8 mmHg. 

Radial artery pressure measured by sphygmomanometry (125 mmHg in the example). 
DP: pressure gradient between peak aortic systolic pressure and mid-systolic left atrial pressure, which can be calculated (simplified Bernoulli equation, P= v² x 4) from the peak velocity of mitral regurgitation;
a: left atrial peak a pressure
AOP: Aortic pressure
LAP: left atrial pressure;
LAPms: left atrial mid-systolic pressure;
LVP: left ventricular pressure
v: left atrial peak v pressure.

Right panel: transesophageal evaluation of mitral regurgitation.