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Evaluation of left ventricular function based on simulated systolic flow dynamics computed from regional wall motion
R T Schoephoerster1, C L Silva, G Ray
1Department of Mechanical Engineering, Florida International University, Miami 33199.
Journal of Biomechanics
|February 1, 1994
Summary
New diagnostic parameters for left ventricular (LV) function were developed using computational fluid dynamics. The central ejection region (CER) coefficient shows promise for assessing global LV function in coronary artery disease.
Area of Science:
- Cardiovascular Physiology
- Biomedical Engineering
- Computational Fluid Dynamics
Background:
- Left ventricular (LV) chamber flow dynamics are significantly influenced by regional LV wall motion.
- Assessing LV function requires diagnostic parameters that capture the complex interplay between wall motion and intracardiac flow.
Purpose of the Study:
- To compute LV chamber flow, velocity, and pressure distributions to derive novel diagnostic parameters.
- To evaluate the utility of local pressure gradients and the central ejection region (CER) coefficient for assessing LV function, particularly in ischemic coronary artery disease.
Main Methods:
- Utilized two-dimensional Navier-Stokes equations solved via the finite analytic method for unsteady, viscous, incompressible flow.
- Calculated LV chamber flow fields from ventriculograms of normal and ischemic hearts, and simulations with abnormal wall motion.
- Defined and computed local pressure gradients and the central ejection region (CER) coefficient (R) as LV assessment parameters.
Main Results:
- Local pressure gradients were reduced in ischemic regions but also in normal regions with abnormal wall motion, limiting their localization accuracy for coronary occlusion.
- The time-averaged CER coefficient was significantly lower in diseased hearts (0.453) compared to normal hearts (0.709).
- The CER shifted towards abnormal wall motion regions, and the CER coefficient decreased with increasing severity of wall motion abnormality.
Conclusions:
- The local wall pressure gradient may indicate the presence of disease but is not ideal for localizing coronary occlusion.
- The CER coefficient offers a sensitive, quantitative measure of global LV function, detecting regional and temporal abnormalities and compensatory actions missed by global parameters.
- The CER coefficient shows potential as a valuable diagnostic tool for assessing LV function in conditions like coronary artery disease.