Equations-1.txt

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Author:
liukuf
ID:
87212
Filename:
Equations-1.txt
Updated:
2011-05-22 17:44:32
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ECHO Equations
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ECHO Equations
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  1. Frequency
    f=cycles/s=Hz
  2. Wavelength(¥)=
    ¥=v/f=1.43mm/mHz
  3. Doppler equation
    • V=v x change freq/doppler shift
    • Higher velocity --> higher doppler frequency shift
  4. Bernoulli's equation
    • 4V(2) assumes prox velocity <1.
    • When LVOT/ PS
    • 4[V2(2) - V1(2)]
  5. Stroke volume
    SV=EDV-ESV
  6. EF% by volumes
    • SV/EDV X 100%
    • EDV-ESV/EDV X 100%
  7. Wall stress
    • Pressure(P) x Ventricular Radius(R) /2 x wall thickness
    • Analogy balloon
    • Bigger balloon with more air pressure has thinner wall & increased wall stress
  8. Stroke Volume
    SV=CSA x VTI
  9. Cardiac Output
    SV(ml) x HR(beats/min) / 1000mL/L
  10. dP/dT is Rate of pressure rise over time is a load-independent measure of LV function.
    • dP/dT=32mmHg/ time from 1to 3 m/s MR CW jet (sec)
    • Normal is > 1200
  11. PAP
    4(Vtr)2 + RAP
  12. PAP with significant PS
    [4(Vtr)2 + RAP] - 4[(Vrv)2 - (Vpa)2]
  13. PVR
    10(Vtr)/VTI rvot
  14. AVA continuity
    .785 x D lvot x VTI lvot/ VTI as
  15. Velocity ratio
    • V lvot/ V as
    • >0.5 mild
    • <0.25 severe
  16. MVA(Mitral stenosis) by P1/2t
    220/P1/2t
  17. Aortic Regurgitation volumes
    • RVav=tSVav-fSVmv
    • ROA=RV/VTIav
    • RF=RVav/TSVx100%

    • Severe Mild
    • RV >60 <30
    • RF >50 <30
    • ROA>0.30 <0.10
  18. Aortic Regurgitation jet width/LVOT%
    • Severe >65%
    • Mild <25%
  19. AR vena contracta
    • Severe >0.6
    • Mild <0.3
  20. AR pressure 1/2 t
    • Severe <200ms
    • Mod Severe 200-350
    • Moderate 350-500
    • Mild >500
  21. Mitral Regurgitation volumes
    • RV=tSVmv-fSVlvot
    • ROA=RVmv/VTImv
    • RF=RVmv/SVmv x100%

    • Severe Mild
    • RV >60 <30
    • RF >50% <30%
    • ROA >0.4. <0.20
  22. MR jet area
    • Severe >40% LA
    • Mild <20% LA
  23. MR Vena Contracta
    • Severe >0.7cm
    • Mild <0.3cm
  24. MR PISA
    • Rflow=2(pi)r(2) x Va
    • =6.28 r(2) x Va
    • ROA=RFlow/Vmr
    • RV=ROA x VTImr

    • Severe
    • ROA >0.4 cm2
    • RV >60
  25. Aortic dilation with age.
    Predicted sinus diamension.
    • Age 18-40
    • 0.97 + (1.12 BSA)
    • Age >40
    • 1.92 + (0.75 BSA)
  26. Qp:Qs
    Dpa(2) x VTI pa / Dlvot(2) x VTI lvot
  27. What is normal fractional shortening?
    24-40%
  28. Index of Myocardial Performance (IMP)
    [MR/tr duration - LVOT/rvot duration] / LVOT/rvot duration

    • Norm < 0.40
    • mild 0.4-0.5
    • Mod 0.6-0.9
    • Sev > 0.9
  29. PA acceleration time
    • Estimates mean PA pressure.
    • 79 - (0.45 x Accel t)
    • HR must be between 60-80.
    • Not valid with asd or vsd
  30. Simplified continuity equation.
    • [(3.0 x BSA x 1000) / HR] / AVvti = AVA cm2
    • Assume nl lvot sv
  31. AVA index c/w severe AS
    <= 0.45
  32. Calc AR ERO by vol, what considered severe
    • AV regurg vol / VTIar
    • (SVav - SVmv) / VTIar
    • >29 = severe
  33. Calc AR regurg fraction by vol, What is moderate.
    • (SVav - SVmv) / SVav
    • Moderate = 30-50%
    • *invalid with significant MR
    • *not well validated
  34. Expected AV decel rate for moderate AR.
    • 2 - 3.5 m/sec2
    • *least reliable
  35. Calc p1/2t AR
    What are mild, mod, sev parameters.
    • mSec x 0.29
    • Mild >500mSec
    • Severe <200mSec

    *least reliable
  36. AR jet/LVOT diameter ratio for moderate AR.
    • 25-64% mod
    • <25% mild
    • >64% sev
  37. AR jet/LVOT area ratio for moderate AR
    • 5-59% mod
    • <5% mild
    • >59% sev
  38. EF calculation Quinones
    (LVEDd2 - LVEDs2) / LVEDd2 x 100%
  39. PVa velocity >0.35 m/sec indicates
    Increased LA pressure/LVEDP
  40. PISA calc
    Flow rate
    ERO
    RV
    • 2 pi r2 x Va = flow rate
    • 6.28 r2 x Va / peak Vmr = ERO cm2
    • ERO cm2 x VTI mr = RV
  41. Simplified MVA by p1/2 t
    759 / decel time

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