# ECHO

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1. Frequency
f=cycles/s=Hz
2. Wavelength(¥)=
¥=v/f
3. Doppler equation
• V=c x (Fs - Ft) /[2 Ft(cos 0)]
• V=1.54 x change freq/angle
• Higher velocity --> higher doppler frequency shift assume cos 0=1(beam parallel to flow)
4. Bernoulli's equation
• 4V(2) assumes prox velocity <1.
• When LVOT/ PS
• 4[V2(2) - V1(2)]
5. Stroke volume
• SV=EDV-ESV
• SV=CSA X TVI
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. Cardiac Output
SV(ml) x HR(beats/min) / 1000mL/L
9. 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 in sec)
• Normal is > 1200
• Abn < 1000
10. PAP
4(Vtr)2 + RAP
11. PAP with significant PS
[4(Vtr)2 + RAP] - 4(Vrv-Vpa)
12. PVR
10(Vtr)/VTI rvot
13. AVA continuity
.785 x D lvot x VTI lvot/ VTI as
14. Velocity ratio
• V lvot/ V as
• >0.5 mild
• <0.25 severe
15. MVA(Mitral stenosis) by P1/2t
220/P1/2t
16. 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
17. AR vena contracta
• Severe >0.6
• Mild <0.3
18. AR pressure 1/2 t
• Severe <200ms
• Mod Severe 200-350
• Moderate 350-500
• Mild >500
19. 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
20. MR jet area
• Severe >40% LA
• Mild <20% LA
21. MR Vena Contracta
• Severe >0.7cm
• Mild <0.3cm
22. MR PISA
• Rflow=6.28 r2 x Va
• ERO=RFlow/Vmr
• RV=ERO x VTImr

• Severe
• ERO >0.4 cm2
• RV >60
23. Aortic dilation with age.
Predicted sinus diamension.
• Age 18-40
• 0.97 + (1.12 BSA)
• Age >40
• 1.92 + (0.75 BSA)
24. Qp:Qs
D pa2 x VTI pa / D lvot2 x VTI lvot
25. What is normal fractional shortening?
24-40%
26. Index of Myocardial Performance (IMP)
LIMP or RIMP
[MR or tr duration - LVOT or rvot duration] / LVOT or rvot duration

• Norm < 0.40
• mild 0.4-0.5
• Mod 0.6-0.9
• Sev > 0.9
27. 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
28. Simplified continuity equation.
• [(3.0 x BSA x 1000) / HR] / AVvti = AVA cm2
• Assume nl lvot sv
29. AVA index c/w severe AS
<= 0.45
30. Calc AR ERO by vol, what considered severe
• AV regurg vol / VTIar
• (SVav - SVmv) / VTIar
• >0.29 = severe
31. Calc AR regurg fraction by vol, What is moderate.
• (SVav - SVmv) / SVav
• Moderate = 30-50%
• *invalid with significant MR
• *not well validated
32. Expected AV decel rate for moderate AR.
• 2 - 3.5 m/sec2
• *least reliable
33. Calc p1/2t AR
What are mild, mod, sev parameters.
• mSec x 0.29
• Mild >500mSec
• Severe <200mSec

*least reliable
34. AR jet/LVOT diameter ratio for moderate AR.
• 25-64% mod
• <25% mild
• >64% sev
35. AR jet/LVOT area ratio for moderate AR
• 5-59% mod
• <5% mild
• >59% sev
36. EF calculation Quinones
(LVEDd2 - LVEDs2) / LVEDd2 x 100%
37. PVa velocity >0.35 m/sec indicates
Increased LA pressure/LVEDP
38. 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
39. Simplified MVA by p1/2 t
759 / decel time
 Author: liukuf ID: 94600 Card Set: ECHO Updated: 2011-07-23 11:47:23 Tags: equations Folders: Description: echo review Show Answers: