Doppler echocardiography showing estimation of pulmonary artery systolic pressure using tricuspid regurgitation (TR) velocity

(A) Continuous wave Doppler showing tricuspid regurgitation (TR). Measurement of peak TR velocity should be performed at the modal frequency (point 1) rather than at the point of highest visible signs (point 2).
(B) Gain settings which are too low do not allow for appropriate visualization of the TR jet, leading to underestimation of the amount of TR and inability to accurately estimate pulmonary artery systolic pressure (PASP).
(C) PASP is estimated using the modified Bernoulli equation; PASP in the absence of right ventricular outflow obstruction is equivalent to right ventricular systolic pressure = right atrial pressure + [4 *(TR velocity)²].