CARDIOVASCULAR FLOW DYNAMICS--IN VIVO STUDIES

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The current year's efforts on this project have continued studies of intracardiac flow dynamics with spectral and two-dimensional color Doppler ultrasound for quantifying pathophysiologic hemodynamic abnormalities. Based upon hydrodynamic principles (jet flux theory, momentum continuity preservation, centerline acceleration/.deceleration, proximal flow convergence and turbulent/viscous interactions), temporal and spatial quantitation of low events is possible. Digital data acquisition and analysis permits spatial resolutions of 0.3 mm with temporal resolutions of 5 msec. Quantitative techniques have been applied to : 1) mitral regurgitation, 2) aortic regurgitation and 3) aortic stenosis and 4) stenotic lesions in prosthetic valves. Three major areas have been under investigation: 1) proximal flow convergence and acceleration profiles, 2) turbulent/viscous interactions and 3) dynamic changes in regurgitant and stenotic orifice areas. Such studies explore fundamental physical principles, examining methodologies and validating techniques with the goals of demonstrating applicability and utility of non invasive Doppler flow imaging to obtain clinically relevant quantitative information.