| Parameter |
Description |
Calculation |
| Sound |
Speed of sound |
V = f · λ |
| |
Sound velocity constant in soft tissue |
1540 = f · λ |
| |
Nearfield length |
L = r² / λ |
| |
Frequency |
f = 1 / T |
| Doppler |
Doppler formula |
ΔF = 2·f0·v / c · cosα |
| |
Doppler shift |
PRF = 2 · f doppler |
| |
Nyquist limit |
Aliasing = PRF / 2 |
| Qs/Qp |
Shunt calculation |
πr² · VTI lvot / πr² · VTI rvot |
| MVA |
Pressure half time |
MVA = 220/PHT |
| TVA |
Pressure half time |
TVA= 190/PHT |
| MPI |
Tei index |
MPI = (IVCT + IVRT) / ET |
| PISA |
Flowrate |
πr² · Vn |
| ERO |
Effective regurgitant orifice |
Flowrate / Vmax MR |
| |
Regurgitation Volume |
ERO · VTI MR |
| Output |
Stroke volume |
πr² · VTI lvot |
| |
Cardiac output |
SV · HF |
| AVA |
Continuity Equation |
AVA = πr² · VTI lvot / VTI AoV |
| Pressure |
Modified Bernoulli equation |
ΔP = 4 (V2² - V1²) |
| |
Simplified Bernoulli equation |
ΔP = 4 · V² |
| PA pressure |
Systolic |
4 x (TR Vmax)² + estimated RAP |
| |
Diastolic |
4 x (PR Ved)² + estimated RAP |
| |
Mean |
0.3 x systolic PAP + 0.6 x diastolic PAP |
| |
|
90 - (0.62 x AccT) when AccT < 120ms |
| |
|
4 x (PR Vmax)² + estimated RAP |
| |
|
TR PGmean + estimated RAP |
| LV |
LV Volume |
(IVS + LVIDd + PW)³ |
| |
Blood volume |
(LVIDd)³ |
| |
Myocardial volume |
(IVS + LVIDd + PW)³ - (LVIDd)³ |
| |
Relative wall thickness |
2 x PWd / LVIDd |
| |
LV mass |
0.8(1.04((LVIDd+IVSd+PWd)³−LVIDd³))+0.6 |
| |
LV mass index |
LV mass / Body surface area |
