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Chapter 8: References 195
References
Mean Velocity (Vmean) in cm/s
Vmean = mean velocity
Mitral Valve Area (MVA) in cm
2
Reynolds, Terry. The Echocardiographer’s Pocket Reference. 2nd ed., School of Cardiac Ultrasound,
Arizona Heart Institute, (2000), 391, 452.
MVA = 220/PHT
where: PHT = pressure half time
Note: 220 is an empirical derived constant and may not accurately predict mitral valve area in mitral
prosthetic heart valves. The mitral valve area continuity equation may be utilized in mitral prosthetic heart
valves to predict effective orifice area.
Pressure Gradient (PGr) in mmHG
Oh, J.K., J.B. Seward, A.J. Tajik. The Echo Manual. 2nd ed., Lippincott, Williams, and Wilkins, (1999),
64.
4 * (Velocity)
2
Peak E Pressure Gradient (E PG)
EPG = 4 * PE
2
Peak A Pressure Gradient (A PG)
APG = 4 * PA
2
Peak Pressure Gradient (PGmax)
PGmax = 4 * PV
2
Mean Pressure Gradient (PGmean)
PGmean = 4 * Vmax
2
Pressure Half Time (PHT) in msec
Reynolds, Terry. The Echocardiographer’s Pocket Reference. 2nd ed., School of Cardiac Ultrasound,
Arizona Heart Institute, (2000), 391.
PHT = DT * 0.29
where: DT = deceleration time
Stroke Volume (SV) Doppler in ml
Oh, J.K., J.B. Seward, A.J. Tajik. The Echo Manual. 2nd ed., Lippincott, Williams, and Wilkins, (1999),
40, 59, 62.
SV = (CSA * VTI)
CSA = Cross Sectional Area of the LVOT
VTI = Velocity Time Integral of the aortic valve