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Transmitral Flow Analysis by Means of Computational Fluid Dynamics on Unstructured Grids
Published in J. Middleton, M. L. Jones, G. N. Pande, Computer Methods in Biomechanics & Biomedical Engineering – 2, 2020
C. Capozzolo, F. M. Denaro, F. Sarghini
The diastolic function is the part of the cardiac cycle characterised by the fact that blood flows through the mitral valve orifice causing left ventricular filling. To quantify the diastolic left ventricular performance, it has been generally useful the analysis of the pattern of left ventricular filling obtained, as example, with the aid of Doppler measurements (Fig.l). Myocardial relaxation begins in the latter part of systole and causes a steep exponential fall in infra-ventricular pressure. This fall produces a pressure gradient that accelerates the blood from left atrium into the left ventricle, resulting in a rapid early filling (E wave). During the filling, left ventricular pressure increases, with general properties depending on ventricular compliance, and atrio-ventricle gradient pressure decreases and transiently reverses. Thus, little left ventricular filling occurs during the midportion of diastole. Finally, atrial contraction increases atrial pressure late in diastole, producing blood to flow again in the left ventricle (A wave) until to the closure of mitral valve. It appears evident that, to qualify the diastolic performance, the only velocity patterns result insufficient being them related only to pressure difference and therefore, in some cases, subject to misleading [e.g., 6, 7]. This description of the diastole results useful to understand the hypotheses adopted in the mathematical model. In particular, the 2-D geometry clearly represents only a rough assumption and fully 3-D case should be considered.
Heart Imaging
Published in Margarida M. Barroso, Xavier Intes, In Vivo, 2020
Leonardo Sacconi, Claudia Crocini
Doppler imaging exploits the Doppler shift principle of a moving target to determine blood flow velocity and direction. Using a pulsed-wave, it is possible to determine blood flow velocity and calculate peak velocities, ejection time (ET), and velocity time intervals. Transmittal flow velocity profiles can provide useful insights of diastolic function, including isovolumic contraction and relaxation times, ratio of early (E)-to-late (atrial, A) ventricular filling velocities (E/A), and deceleration of E wave. Fusion of E and A waves may be an indicator of diastolic dysfunction. However, the rapid heart rate of rodents (especially mice and rats) may also result in partial or complete fusion of E and A waves.
Intraventricular vector flow mapping 3-D by triplane Doppler echocardiography
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
F. Vixege, P. Y. Courand, P. Blanc-Benon, S. Mendez, F. Nicoud, D. Vray, D. Garcia
Heart failure affects the heart’s ability to meet the oxygen needs of the organs. It concerns more than one million people in France. It can be defined by the reduced capacity of the heart to be filled with blood (diastolic dysfunction) and/or emptied (systolic dysfunction). Although systolic dysfunction is relatively easy to diagnose, the diagnosis of diastolic dysfunction is more challenging. The accessibility of echocardiography, and its ability to provide information non-invasively and in real time, makes ultrasound the preferred technique for evaluating left ventricular diastolic function. However, the diagnosis of diastolic dysfunction often remains uncertain, as the recommended ultrasound indices may lead to conflicting conclusions. Since intracardiac blood flow is very sensitive to changes in the myocardium, we hypothesized that a thorough examination of intraventricular blood flow by color Doppler echocardiography could improve the assessment of diastolic function in patients with heart failure.
Intraventricular vector flow mapping by 3-D doppler echo
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
F. Vixege, P.Y Courand, F. Nicoud, D. Vray, D. Garcia
Heart failure is the cardiomyopathy that will have the greatest impact on the lives of French in the coming decades. It is a cardiac disease that affects the ability of the heart to meet the oxygen needs of the organs. It involves more than 1 M people in France, and its prevalence will double by 2028. Heart failure can be identified by the reduced ability of the heart to fill with blood (diastolic dysfunction) and/or to empty (systolic dysfunction). Although systolic dysfunction is easily diagnosed, the diagnosis of diastolic dysfunction (diastology) can be challenging. The accessibility of echocardiography, and its ability to provide non-invasive information in real time, make ultrasound the essential technique for evaluating diastolic function of the left ventricle. However, the diagnosis of diastolic dysfunction often remains unclear since the recommended echographic indices may lead to discordant conclusions. As intracardiac blood flow is very sensitive to changes of the myocardium, we hypothesized that a more in-depth examination of the intraventricular blood flow by echocardiographic color Doppler could improve diastology in patients with heart failure.