Echocardiography Techniques I Exam 1 Practice

The relationship being tested is that regurgitant volume per beat in mitral regurgitation equals the product of the effective regurgitant orifice area and the velocity-time integral of the MR jet. EROA represents the size of the leak, while VTI_MR is the distance that blood travels during the regurgitant jet in one heartbeat, obtained by integrating the MR jet velocity over time. Multiplying these gives the total volume of blood regurgitated per beat: EROA × VTI_MR, and the units work out to milliliters. This also makes intuitive sense: a larger orifice lets more blood flow per unit time, and a longer duration of regurgitation (captured by a larger VTI_MR) increases the total amount of regurgitated blood. If you divided EROA by VTI_MR or added them, the units wouldn’t yield a volume, and saying regurgitant volume is independent of EROA contradicts the physics of flow across an orifice.