User guide

80 Measurement publications and terminology
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.
MV Flow Rate in cc/sec
Reynolds, Terry. The Echocardiographer’s Pocket
Reference
. 2nd ed., School of Cardiac Ultrasound,
Arizona Heart Institute, (2000), 396.
Flow = 6.28 (r
2
) * Va
where: r = radius
Va = aliasing Velocity
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.
PGr = 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 = Average of pressure gradients/Duration
of flow
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
Proximal Isovelocity Surface Area (PISA)
in cm
2
Oh, J.K., J.B. Seward, A.J. Tajik. The Echo Manual.
2nd ed., Boston: Little, Brown and Company,
(1999), 125.
PISA = 2 r
2
where: 2 = 6.28
r = aliasing radius
Qp/Qs
Reynolds, Terry. The Echocardiographer’s Pocket
Reference.
2nd ed., School of Cardiac Ultrasound,
Arizona Heart Institute, (2000), 400.
Qp/Qs = SV Qp site/SV Qs site
SV sites will vary depending upon the location of
the shunt.
Regurgitant Fraction (RF) in percent
Oh, J.K., J.B. Seward, A.J. Tajik. The Echo Manual .
Boston: Little, Brown and Company, (1999), 125.
RF = RV/ MV SV
where: RV = Regurgitant Volume
MV SV = Mitral Stroke Volume
Regurgitant Volume (RV) in cc
Reynolds, Terry. The Echocardiographer’s Pocket
Reference.
School of Cardiac Ultrasound, Arizona
Heart Institute, (2000), 396, 455.
RV = ERO * MR VTI
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