ECHO 2013 / Hemodynamics I. Basic Calculations SV and CO, Valve Areas and Intracardiac Pressures
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Stroke Volume and Cardiac Output
•Systemic Arterial Stroke Volume:
Aortic: typically measured at the aortic anulus (or LVOT)
•VTI measured by tracing the peak velocity envelope of pulsed flow profile in systole
Mitral: measure mitral anulus in 4 chamber view
•VTI measured by tracing the peak velocity envelope in diastole
•Systemic Venous Stroke Volume:
Pulmonary Artery: measured at the anulus
•VTI measured by tracing the peak velocity envelope in systole
Stroke Volume
LVOT Stroke
Volume
RVOT Stroke
Volume
Shunt Calculation: Correlation with Cath
In patients with ASD:
•Correlation of pulmonary and systemic flows = 0.93 and 0.92
•Derived Qp/Qs
R = 0.82
SEE ± 0.21
Cacciapuoti F, et al. Int. J Cardiol 1986; 13:64
AR Quantitative Doppler
Doppler |
Mild |
Moderate |
Severe |
Parameter |
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Regurgitant |
< 30 cc |
30-59 cc |
> 60 cc |
Volume |
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Regurgitant |
< 30% |
30-39 % |
> 50 % |
Fraction |
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40-49 % |
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Regurgitant |
< 10 mm2 |
10-19 mm2 |
> 30 mm2 |
Orifice Area |
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20-29 mm2 |
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Zoghbi et al J Am Soc Echocardiogr
2003;16:777-802.
Volumetric Measurements
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Systole |
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Diastole |
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Technical Pitfalls: Misplacement of sample
volume
Tips MV
1.85 m/s
MV Annulus |
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1.6 m/s |
LA |
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1.4 m/s |
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MR Quantitative Doppler
Doppler |
Mild |
Moderate |
Severe |
Parameter |
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Regurgitant |
< 30 cc |
30-59 cc |
> 60 cc |
Volume |
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Regurgitant |
< 30% |
30-39 % |
> 50 % |
Fraction |
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40-49 % |
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Regurgitant |
< 20 mm2 |
20-29 mm2 |
> 40 mm2 |
Orifice Area |
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30-39 mm2 |
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Zoghbi et al J Am Soc Echocardiogr 2003;16:777-802.
Mitral Regurgitant Volume: Correlation with Invasive Measures
• Other methods of estimating SVt
Teichholz volume
Simpson’s method
• Using any method in patients, r = 0.82
Ascah KG et al. Circulation 1985;72:381
Doppler Echocardiography
Part 3: Conservation of Mass
and the Continuity Equation
Continuity Equation
•Continuity Equation utilizes the conservation of mass theory
Stroke Volume1 = Stroke Volume2
(Area x TVI)1 = (Area x TVI)2
Area2 = (Area x VTI)1 / (VTI2)
•Area AV = Area LVOTx VTILVOT/VTIAV
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A1 |
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V1 |
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x |
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Area AV = |
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V2 |
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V2
A2
V1
A1