Formulas

Most common formulas used in echocardiographic calculations

Parameter Description Formula
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
Shunt calculation Qs/Qp 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 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 Gemodified 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
LV mass (IVS + LVIDd + PW)³ - (LVIDd)³ · 1.05
LV mass (Devereaux) 1.04 [(IVS + LVIDd + PW)³ - (LVIDd)³] - 13.6

 

 

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