Blood Flow In Ventricle Research Articles

Computational Analysis of Flow Structures in Turbulent Ventricular Blood Flow Associated With Mitral Valve Intervention.

Cardiac disease and clinical intervention may both lead to an increased risk for thrombosis events due to a modified blood flow in the heart, and thereby a change in the mechanical stimuli of blood cells passing through the chambers of the heart. Specifically, the degree of platelet activation is influenced by the level and type of mechanical stresses in the blood flow. In this article we analyze the blood flow in the left ventricle of the heart through a computational model constructed from patient-specific data. The blood flow in the ventricle is modelled by the Navier-Stokes equations, and the flow through the mitral valve by a parameterized model which represents the projected opening of the valve. A finite element method is used to solve the equations, from which a simulation of the velocity and pressure of the blood flow is constructed. The intraventricular blood flow is complex, in particular in diastole when the inflow jet from the atrium breaks down into turbulent flow on a range of scales. A triple decomposition of the velocity gradient tensor is then used to distinguish between rigid body rotational flow, irrotational straining flow, and shear flow. The triple decomposition enables the separation of three fundamentally different flow structures, that each generates a distinct type of mechanical stimulus on the blood cells in the flow. We compare the results in a simulation where a mitral valve clip intervention is modelled, which leads to a significant modification of the intraventricular flow. Further, we perform a sensitivity study of the results with respect to the positioning of the clip. It was found that the shear in the simulation cases treated with clips increased more compared to the untreated case than the rotation and strain did. A decrease in valve opening area of 64% in one of the cases led to a 90% increase in rotation and strain, but a 150% increase in shear. The computational analysis opens up for improvements in models of shear-induced platelet activation, by offering an algorithm to distinguish shear from other modalities in intraventricular blood flow.

Continuous Apex to Left Ventricle Blood Flow Pattern in Hypertrophic Cardiomyopathy with Apical Aneurysm and Midventricular Obstruction

A 42-year-old female presented with chest pain, noted to have systolic and diastolic murmurs on physical examination and left ventricular hypertrophy on the electrocardiogram. Echocardiography with contrast enhancement revealed hypertrophic cardiomyopathy (HCM) with apical aneurysm and mid left ventricular cavity obstruction. Doppler interrogation showed continuous systolic and diastolic flow from the apex to left ventricle (LV) with a transient deceleration giving rise to a notched pattern. Myocardial ischemia of the apex was demonstrated on adenosine nuclear scintigraphy without epicardial coronary obstruction on angiography. This case demonstrates a novel Doppler pattern with continuous apex to LV flow in HCM in the setting of apical ischemia that may account for the formation of the aneurysm.

Assessment of the hemodynamics of left ventricle in ventricular aneurysm during the contraction phase by vector flow mapping

Objective To evaluate the systolic function of left ventricle in myocardial infarction(MI)patients with ventricular aneurysm and the changing law of blood flow in ventricle with regional abnormality of wall movement by vector flow mapping (VFM).Methods Tirty-one MI patients with ventricular aneurysm and 35 healthy participants were enrolled in this study.The characteristic of vector and streamline,and the changing of the velocity gradient in left ventricular outflow tract (LVOT), and the average flow quantity through aneurysm neck were detected in the isovolumic contraction period, the rapid ejection period and the slow ejection period by VFM.Results The distinction between aneurysm and control group was mainly the persistance of vortex in aneurysm.The size of vortex in aneurysm was highly correlated with that measured by 2-D ultrasound(P ＜0.01).The percentage of vortex duration to cardiac cycle in patients group was significantly greater than that in control group(P ＜0.01).In the early systolic contraction the velocity gradient in LVOT in patients with ventricular aneurysm was smaller than that of control group(P ＜0.05).The average flow through aneurysm neck was notablely decreased compared with control group(P ＜0.01).Conclusions VFM can reveal the hemodynamics of left ventricle with aneurysm directly as well as quantitively measure the regional velocity and flow quantity.VFM can evaluate the systolic function of left ventricle exactly. Key words: Echocardiography ; Myocardial infarction; Heart aneurysm; Hemodynamic phenomena

Regional blood flow during acute heart failure in dogs. Role of adipose tissue perfusion in regulating plasma-free fatty acids

The effect of acute ischaemic left ventricular failure on regional blood flow and the possible role of adipose tissue perfusion in the regulation of plasma FFA during failure were examined. Left ventricular failure was induced in closed-chest anaesthetized dogs by injection of 50 micrometer plastic microspheres into the left main coronary artery. Regional blood flow, measured with tracer microspheres, showed a redistribution of cardiac output after the induction of failure. Adipose cardiac output (P less than 0.05), while skeletal muscle and pancreatic blood flow decreased about in proportion to the decrease in cardiac output. There was only a moderate decrease in renal blood flow and in left ventricular myocardial blood flow. In the free wall of the right ventricle blood flow was unchanged. There was a marked decrease in plasma FFA during failure (P less than 0.05), which could not be attributed to enhanced FFA turnover rate nor to inhibition of adipose tissue lipolysis, as plasma glycerol tended to increase. The marked decrease in adipose tissue blood flow during failure suggests that plasma FFA decreased due to trapping of FFA in adipose tissue.