Continuous wave Doppler across the aortic valve in a patient with aortic regurgitation (AR)

For assessment of the severity of aortic regurgitation, a useful parameter is the pressure half time (PHT) using continuous wave Doppler. The PHT is computed by placing a line (arrow) along the slope of velocity decay or deceleration time (A to B); in this patient, the PHT is 99 ms. Aortic regurgitation PHT values of less than 200 ms are consistent with severe aortic regurgitation. In addition, with severe aortic regurgitation, the density of the diastolic regurgitant signal is nearly equal to that of the antegrade systolic flow signal across the aortic valve, consistent with a high regurgitant volume.