Simulation of the beating heart, taking into account the action of the diaphragm and the flow field

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Year: Not Specified University Degree: Master's degree Category: Facilities - Mechanics
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  • Summary of Simulation of the beating heart, taking into account the action of the diaphragm and the flow field

    Master thesis in the field of mechanical engineering, applied design

    1-1-Introduction

    All humans know that the heart is a vital organ in the human body, so that we cannot live without it. But with a purely mechanical view, the heart is just a pump; A very complex and important pump; And in terms of being a pump, like all pumps, there is a possibility of clogging, failure or needing to be repaired. This sensitivity of the heart as a vital organ in the body is part of why we need to know how the heart works.

    In 2004, heart disease accounted for 36% of deaths worldwide and was also the leading cause of death in the United States. Approximately 2,000 people in the United States die of heart disease each day, which is one death every 44 seconds. In Iran, according to the Minister of Health, 300 heart patients die every day, which means that cardiovascular diseases cause the loss of 23.4% of the lives of the country's people. The good news is that the death rate from heart disease is decreasing. Unfortunately, heart diseases cause people to die suddenly, and many patients succumb to death before reaching the hospital.

    In order to help prevent and treat heart diseases, mathematical modeling of the heart has become an important and significant topic for researchers. A virtual model that can be used to make an intelligent assistant for doctors.  The use of software simulation and computational methods such as finite element analysis will be useful for investigating the structure-fluid interaction of the human heart. Creating a suitable computational model according to the geometry and anatomy of the heart, modeling the mechanical properties of the heart tissue and analyzing the structure-fluid interaction using the built model can be used as a useful tool in medical applications. Because performing this analysis on the computational model is the same as a real surgery. This application; virtual surgery [1]; It will be a powerful tool in medical applications, so that the doctor can know the results of his work before surgery. For example, in surgery and pulmonary valve replacement [2]; Knowing that, a place of the right ventricular wall that has minimum stress-strain is a suitable place for cutting; By being aware of the results of this analysis and knowing the maximum-minimum stress-strain values, the doctor will be able to correctly diagnose the cutting site. Elastic walls, pulsating movement of blood flow, separate cavities, electric current, fluid and solid interaction, as well as biological processes of the heart are reasons for the complexity and difficulty of the modeling path. rtl;"> 

    The heart is a muscular organ responsible for pumping blood into the arteries by pulsating movements. This cone-shaped organ is in the form of a muscular bag almost in the middle of the chest space, first it is hidden in the heart of a dense and wide sponge filled with air (lungs) and then it is protected by a very hard (but flexible) bony shelf. Approximately seventy-five percent of all hearts are located on the left side of the human body and twenty-five percent are located on the right side of the human body. The dimensions of the heart in an adult person are 6 x 9 x 12 cm and the weight is 300 grams in men and 250 grams in women.

    The heart has four chambers. Right atrium[4], right ventricle[5], left atrium, left ventricle. (Left and right always refer to the individual). The heart is divided into right and left halves by a vertical muscular wall. The right half corresponds to venous blood and the left half corresponds to arterial blood. Each of the two right and left halves are again divided by a thinner horizontal muscle blade into two separate sub-cavities.

    The upper cavities, which are smaller and thinner, are called the atrium and receive blood. The lower chambers, which are larger and thicker, are the ventricles of the heart and pump the blood received to other parts of the body.So the heart consists of four chambers: two small chambers at the top (right and left atria) and two large chambers at the bottom (right and left ventricles).

    Coronary veins or coronary veins are the vessels that feed the heart muscle, which cover the whole muscle and are among the most important and vital vessels in the human body, because if these vessels are blocked, a heart attack will occur immediately. which can cause death or many complications. Guyton [6]- 1998 [. [15]

    The heart has a base (posterior surface), an apex [7], three surfaces and four sides. The base of the heart is the posterior surface of the heart, which is at the level of T5-T9 seals in the lying position. This surface is located on the right side and is slightly inclined to the back and is formed mainly from the posterior surface of the left atrium and a small part of the posterior surface of the right atrium. The apex of the heart is formed by the left ventricle. [16]

    The heart has four chambers and four valves. The atrium of each side is connected to the ventricle of its side through an orifice. This orifice is controlled by an atrioventricular valve [8]. The right atrium leads to the right ventricle through the tricuspid valve [9]. The left atrium leads to the left ventricle through the mitral valve[10]. These two valves (tricuspid valve and mitral valve) open only towards the ventricles and act like a one-way valve.  The left ventricle leads to the aorta through the aortic valve[11], which is a three-leaf valve. In other words, the mitral valve is the blood flow inlet and the aortic valve is the blood flow outlet for the left ventricle. The right ventricle opens to the pulmonary artery through the pulmonary valve, which is a three-leaf valve.  In other words, the tricuspid valve between the right atrium and ventricle is the blood flow inlet and the pulmonary valve [12] is the blood flow outlet for the right ventricle. The aortic valve opens only towards the aorta and the pulmonary valve opens only towards the pulmonary artery. The mitral valve is the only valve, and all three valves, the aortic valve, the pulmonary valve, and the valve between the right atrium and the right ventricle are three-leaflet. 1-1-1-1-Right atrium The right atrium is responsible for receiving blood from the upper and lower chambers. After circulating throughout the body, venous blood enters the right atrium through these two veins. The blood entering the right atrium enters the right ventricle through the ventriculo-atrial valve.

    1-1-1-2-Right ventricle

    The right ventricle is in the shape of a pyramid of Al-Qaeda triangle, which receives the blood of the right atrium through the atrio-ventricular valve and then through the pulmonary artery. It sends to the lungs. In fetal life, unlike the heart, the lungs do not work and do not receive blood from the right ventricle. Therefore, during the embryonic period, between the right and left atrium of the heart, there is a hole called the oval valve[13], and the blood of the atrium mainly enters the left atrium through this hole instead of going to the right ventricle. With the establishment of pulmonary blood circulation after birth, the oval valve closes some time after birth.

    1-1-1-3-Left atrium

    The left atrium receives the blood sent to the lungs through the right ventricle. This blood enters the left ventricle through the mitral valve.

    1-1-1-4-left ventricle

    The left ventricle is responsible for supplying blood to all organs and tissues. In other words, it is the main and important part of the heart that pumps the blood received from the left atrium through the aorta to the whole body. style="direction: rtl;"> 

    By:

    Rouhollah Pourmand Dashtaki

     

    The main purpose of the current research is to simulate the geometric structure of human heart and the characteristics of its constitution.

  • Contents & References of Simulation of the beating heart, taking into account the action of the diaphragm and the flow field

    List:

    1- First chapter 1

    1-1- Introduction 2

    1-1-1- Heart anatomy 4

    1-1-1-1-Right atrium 7

    1-1-1-2-Right ventricle 7

    1-1-1-3-left atrium 8

    1-1-1-4-left ventricle 8

    1-1-1-5-coronary arteries 9

    1-1-1-6-stimulation-conduction device of the heart 9

    1-1-1-7-cardiac cycle 12

    1-1-1-8-electrocardiogram 16

    1-1-1-9-blood flow in the body 18

    1-1-2- blood viscosity 19

    1-1-2-1-cardiac output 20

    1-1-2-2-heart layers 21

    1-1-2-3-Myocardial layer 21

    2- Chapter Two 23

    2-1- Review of past researches 24

    3- Chapter Three 51

    Description of equations of hyperelastic and viscoelastic materials and equations governing fluid flow field]34,38,42,43 [ 52

    3-1- Introduction 52

    3-1-1- Hyperelastic material 52

    3-1-1-1-Isotropy 53

    3-1-1-2-strain energy density function 53

    3-1-2- Proposed hyperelastic models 60

    3-1-2-1-Neo-Hockin model 60

    3-1-2-2-Money-Rivelin model 61

    3-1-2-3-Arruda-Boyce model 61

    3-1-2-4-Marlowe model 62

    3-1-2-5-Ogden model  62

    3-1-2-6-polynomial model 63

    3-1-2-7-reduced polynomial model 63

    3-1-2-8-van der Waals model 64

    3-1-2-9-Joh model 65

    3-1-2-10-thermal expansion 65

    3-1-3- viscoelastic material 65

    3-1-3-1-history 67

    3-1-3-2-small strain 67

    3-1-3-3-large strain 69

    3-1-4- viscohyperelastic material 70

    3-2- Experimental tests 71

    3-2-1- Uniaxial test 75

    3-3- Arbitrary Lagrange-Euler method 76

    3-4- Fluid flow equations 78

    3-4-1- Moving network method 79

    3-4-2- How to update Moving grid 79

    3-4-3- smoothing by spring elements 80

    3-4-3-1-smoothing based on penetration 81

    3-4-4- governing equations of structure-fluid interaction[39] 84

    3-4-4-1-solution algorithms[38] 85

    3-5- Blood models] 43[89

    4-           Chapter four 91

    4-1-       Modeling the left side of the heart and left ventricle in Mimics software    92

    4-1-1- First step: Simulation of real geometry 93 4-1-2- Reconstruction of real geometry 95 4-1-3 Image processing and three-dimensional volume production 95 4-1-4 Checking how the boundary conditions are 100 4-1-5 Checking the input boundary condition 103 4-1-6 Checking the boundary condition Output 107

    4-1-7- Simulation limitations 109

    4-1-8- Choosing a hyperelastic model for modeling the soft tissue of the heart (myocardium) 113

    Neo-Hockin model 114

    4-1-9- Moony-Rivlen model with two variables 115

    4-1-10- Moni-Rioline model with five variables 116

    4-1-11- Conclusion 118

    120 5-1 Preliminary results obtained in Mimics software 121 5-1-1 Calculation of cardiac ejection fraction 123 5-2 Network study 126 5-2-1 Conclusion 133 5-3 Blood flow field in ventricle Left side of the human heart 134 5-3-1- Blood flow field in the left ventricle with a fixed wall at a constant speed in the mitral valve (inlet of the left ventricle) in the 50% phase 135 5-3-2- Blood flow field in the left ventricle with a fixed wall at a variable speed in the mitral valve (inlet of the left ventricle) in the 50% phase 137 5-4- Structure-fluid in the left ventricle 142

    5-4-1- Network study 143

    5-4-2- Investigating the structure-fluid interaction in the left ventricle unilaterally 145

    5-4-3- Investigating the structure-fluid interaction in the left ventricle bilaterally 151

    6- Chapter                                                                                                                                                      169 6-1 Summary and recommendations 170 Source: [1] Taylor C.A., Hughes T.J. and Zarins C.K. "Finite Element Modeling of Blood Flow in Arteries." Computer Methods in Applied Mechanics and Engineering, Vol. 158, (pp. 155–196), 1998.

    [2] McQueen D.M. and Peskin C.S. "A three dimensional computer model of the human heart for studying cardiac fluid dynamics." ACM Siggraph Computer Graphics, Vol. 34, (pp. 56-60). 2000.

    [3] Stevens C., Remme E., LeGrice I. and Hunter P.J. "Ventricular mechanics in diastole: material parameter sensitivity." Journal of Biomechanics, Vol. 36, (pp.737–748), 2003.

    [4] Mooney R., Sullivan C.O., Ryan J. and Bell C. "The Construction of a Volumetric Cardiac Model for Real-time ECG Simulation." Poster Sessions of the Winter Conference on Computer Graphics. 2003.

    [5] Van Loon R., Anderson P.D. and Van F.N.” A fluid-structure interaction method with solid-rigid contact for heart valve dynamics." Journal of Computational Physics. Vol 217, (pp. 806–823). 2006. [6] Carmody C.J., Burriesci G., Howard I.C and Patterson E.A. "An approach to the simulation of fluid-structure interaction in the aortic valve." Journal of Biomechanics. Vol 39, (pp. 158–169). 2006.

    [7] Vigmond E., Clements, McQueen D.M and Peskin C.S. "Effect of bundle branch block on cardiac output: A whole heart simulation study". Biophysics & Molecular Biology. (pp. 520-542). 2008.

    [8] Alishahi, Marzieh. Thesis entitled Simulation of blood flow in occluded flexible vessel, Shiraz University. (1388).

    [9] Sajjadi, Sayeda Zahra Begum. Dissertation titled geometric simulation of beating heart, Shiraz University. (1390).

    [10] Yongie Z. and Chandrajit B. "Finite element meshing for cardiac analysis". Integrated Data Systems Department, Siemens Corporate Research, NJ, USA. 2004. [11] Yefeng Z., Bogdan G. and Adrian B. "Four-chamber heart modeling and automatic segmentation for 3D cardiac CT volumes". Integrated Data Systems Department, Siemens Corporate Research, NJ, USA. 2008.

    [12]http://health.howstuffworks.com/mentalhealth/depression/questions/depression causes heart attack.htm.

    [13]Bern Q. and Levy R. "Principles of Physiology". 4th Edition. Chapter 23. 2002.

    [14] Katz Am. "Physiology of the heart". 3rd Edition. Chapter 15. 2010.

    [15] Guyton A. and Hall J. Text book of Medical Physiology. Tcheher Co. Vol. 1. 10th Edition. Chapter 9, 14, 20. 1998.

    [16] General anatomy book based on Gray's anatomy, chapter 5. Dr. Fardin Omidi. Tehran, Khosravi Publishing House, 1388.

    [17] General physiology book, second edition, third and fourth chapters. Dr. Ahmad Rostami, Dr. Mehdi Nematbakhsh. Isfahan, University of Medical Sciences, 1388.

    [18] Merrifield R., Long Q., Kilner P.J., Firmin D.N. and Yang G.Z.” Combined CFD/MRI Analysis of Left Ventricular Flow". MIAR, LNCS 3150, (pp.229-236). 2004.

    [19] Long Q., Merrifield R., Kilner P., Firmin D.N and Yang G.Z." Subject-specific computational simulation of left ventricular flow based on magnetic resonance imaging". Journal of Engineering in Medicine. Vol. 154. (pp. 222-475). 2008.

    [20] Hudsmith E., Stefeen E., Jane M., Matthew D. and Stefan N. "Normal human left and right ventricular and left atrial dimensions using steady state free precession magnetic resonance imaging". Journal of Cardiovascular Magnetic Resonance. Vol. 78. (pp. 775–782). 2005.

    [21] Nikoo R., Gosman A., Nigel B., Philip J., Clare L. and David N.” Computational Flow Modeling of the Left Ventricle Based on In Vivo MRI Data: Initial Experience". Annals of Biomedical Engineering. Vol. 29, (pp. 275-283). 2001. [22] Khalafvand S., Zhong L., Hung and T.K.

Simulation of the beating heart, taking into account the action of the diaphragm and the flow field