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Two-dimensional mitral flow velocity profiles in pig models using epicardial Doppler echocardiography
W Y Kim1, T Bisgaard, S L Nielsen
1Department of Thoracic and Cardiovascular Surgery, Skejby Sygehus, Aarhus University Hospital, Denmark.
Journal of the American College of Cardiology
|August 1, 1994
Summary
Blood flow across the mitral valve is not uniform. This non-uniform velocity profile can lead to significant errors in cardiac output calculations using Doppler echocardiography.
Area of Science:
- Cardiovascular fluid dynamics
- Cardiac imaging and hemodynamics
Background:
- Understanding blood flow through the natural mitral valve is crucial for fluid dynamics research.
- Accurate cardiac output estimation using Doppler echocardiography requires detailed knowledge of mitral valve velocity distribution.
Purpose of the Study:
- To investigate the velocity distribution across the natural mitral valve.
- To quantify potential errors in cardiac output measurements due to non-uniform velocity profiles.
Main Methods:
- Epicardial Doppler echocardiography was used in anesthetized pigs to measure mitral valve velocity.
- Two-dimensional velocity profiles were constructed by rotating the ultrasound transducer.
- Time-averaged mitral velocity profiles were analyzed to estimate errors in cardiac output calculations.
Main Results:
- Diastolic mitral velocity profiles exhibited skewness due to vortex formation in the left ventricle.
- The ratio of center sample volume velocity to spatially averaged velocity was 1.13 +/- 0.15.
- Velocity distribution non-uniformity correlated with anterior vortex peak velocity (r = 0.65, p < 0.01).
Conclusions:
- Assuming a flat velocity profile across the mitral valve introduces significant errors in cardiac output measurements.
- Errors can be as high as +13 +/- 15% when using a single sample volume in Doppler ultrasound.