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Numerical Analysis On Simplified 2d Model Of Heart Valve Leaflets During Cardiac Cycle
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Book Synopsis Numerical Analysis on Simplified 2D Model of Heart Valve by : Lee Xin Leong
Download or read book Numerical Analysis on Simplified 2D Model of Heart Valve written by Lee Xin Leong and published by LAP Lambert Academic Publishing. This book was released on 2012 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays, the increasing numbers of heart diseases cases is very worrying although the medication technologies are always improving and moving forward.In this book, numerical modeling was used to study the effect of blood flow velocity and leaflet displacement by different shape of simplified 2D model of heart valve leaflets during cardiac cycle.Five different shapes of mitral valve leaflets and aortic valve leaflets were created and the simulation was performed by using ADINA-Fluid Structure Interaction (FSI). Ellipse shape of leaflets could be chosen as the most suitable shape among these five shapes in further study of heart valve simulati
Book Synopsis Numerical Analysis on Simplified 2d Model of Heart Valve Leaflets During Cardiac Cycle by : Xin Leong Lee
Download or read book Numerical Analysis on Simplified 2d Model of Heart Valve Leaflets During Cardiac Cycle written by Xin Leong Lee and published by . This book was released on 2012 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays, the increasing numbers of heart diseases cases is very worrying although the medication technologies are always improving and moving forward. In this study, the objectives are to investigate the effect of blood flow velocity and leaflet displacement by using different shape of simplified two dimensional heart valve leaflets in the diastolic and systolic condition. Five different shapes of mitral valve leaflets and aortic valve leaflets were created and the simulation was performed by using ADINA-Fluid Structure Interaction. From the result obtained, triangle shape of leaflet showed it had the highest of blood velocity changes and leaflets displacement changes in a period time of one second when compare to the other four shapes whereas the square shape had the lowest performances. The relationship obtained for blood velocity flow and leaflet's displacement changes is same for both mitral valve and aortic valve. The velocity of flow and leaflet's displacement changes for triangle shape in diastolic condition is 68.54 mm/s and 2.171 mm while at systolic condition is 102 mm/s and 5.168 mm respectively for mitral valve. The outcome simulation result shows that large vortex formed behind the leaflet and leaflet deformed when the blood flow into left ventricle is agreed with the result in literature. In conclusion, five different shapes two-dimensional model of mitral valve and aortic valve has been developed and ellipse shape of valve leaflets is predicted to be the most suitable shape in applying for future artificial valve designing due to its good blood velocity flow with the small changes of leaflets displacement. Ellipse shape of leaflets could be chosen as the most suitable shape among these five shapes in further study of heart valve simulation.
Book Synopsis Mathematical and Numerical Modeling of the Cardiovascular System and Applications by : Daniele Boffi
Download or read book Mathematical and Numerical Modeling of the Cardiovascular System and Applications written by Daniele Boffi and published by Springer. This book was released on 2018-11-03 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book comprises contributions by some of the most respected scientists in the field of mathematical modeling and numerical simulation of the human cardiocirculatory system. It covers a wide range of topics, from the assimilation of clinical data to the development of mathematical and computational models, including with parameters, as well as their efficient numerical solution, and both in-vivo and in-vitro validation. It also considers applications of relevant clinical interest. This book is intended for graduate students and researchers in the field of bioengineering, applied mathematics, computer, computational and data science, and medicine wishing to become involved in the highly fascinating task of modeling the cardiovascular system.
Book Synopsis Numerical Simulation of Pulsatile Blood Flow Across a Tilting-disk Mechanical Heart Valve by : Alireza Nejadmalayeri
Download or read book Numerical Simulation of Pulsatile Blood Flow Across a Tilting-disk Mechanical Heart Valve written by Alireza Nejadmalayeri and published by . This book was released on 2007 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: To overcome several clinical challenges involving mechanical heart valves, accurate numerical simulation of blood flow through these devices has been of interest. Since heart disease is the leading cause of death around the world, the hemodynamic study of the heart is of extraordinary interest in the field of bio fluid dynamics. Recent numerical/experimental investigations have shown that mechanical heart valves inherit the "production of sufficiently large shear and turbulent stresses to cause clinical problems such as hemolysis." Due to several parameters including the non-Newtonian behavior of blood, pulsatile waveform, strong blood and tissue interactions, clinical difficulties, etc., experimental examination of blood flow in the heart and its valves is a very difficult task. Therefore, comprehensive numerical analysis of this complex fluid-structure system is essential. However, precise experimental investigations are still imperative for developing appropriate and accurate turbulence models and for validating numerical techniques.In the current computational effort, the first set of objectives was numerical investigations of vortex shedding behind a two-dimensional tilting-disk mechanical heart valve in a straight channel, which is a simplified representation of the mitral position, using first- and several higher-order finite volume schemes as well as examination of the non-Newtonian viscosity effects on shedding frequency and amplitude.
Book Synopsis Cardiovascular Mathematics by : Luca Formaggia
Download or read book Cardiovascular Mathematics written by Luca Formaggia and published by Springer Science & Business Media. This book was released on 2010-06-27 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematical models and numerical simulations can aid the understanding of physiological and pathological processes. This book offers a mathematically sound and up-to-date foundation to the training of researchers and serves as a useful reference for the development of mathematical models and numerical simulation codes.
Book Synopsis Material Behavior of the Anterior Mitral Valve Leaflet from Inverse Finite Element Analysis by : Gaurav Krishnamurthy
Download or read book Material Behavior of the Anterior Mitral Valve Leaflet from Inverse Finite Element Analysis written by Gaurav Krishnamurthy and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The mitral valve (MV) is a bicuspid valve that allows the unidirectional flow of blood from the left atrium (LA) into the left ventricle (LV). MV disease afflicts millions each year worldwide and if sufficiently severe, surgical therapy is indicated. Surgical repair is currently preferred but valve replacement is often required. Current replacement therapy involves implantation of a mechanical valve, associated with anticoagulation/ thromboembolic complications, or a tissue valve, associated with less than ideal durability. To overcome these limitations, a currently important research goal is to create bioengineered autologous tissue valves. A key component of this thrust is to understand more completely the structure and function of native valves which reliably cycle 100,000 times per day, more than 3 billion times in an average lifetime. Toward this end, this thesis presents, for the first time, the material properties of the anterior mitral leaflet in the beating heart. The methodology used in this research is as follows: Surgical preparation and radiopaque marker data acquisition: 16 miniature radiopaque markers were sewn to the MV annulus, 16 to the anterior MV leaflet, and one on each papillary muscle tip in male sheep. 4-D coordinates were obtained from biplane videofluoroscopic marker images (60f/s) during three complete cardiac cycles. Data were acquired sequentially with repeat control runs between saddlehorn electrical pulse stimulation and intravenous administration of esmolol to study the effect of pharmacological agents on mitral leaflet contractility, and vagal nerve stimulation to assess the potential for central neural control. Inverse finite element analysis: A finite element model of the anterior MV leaflet was developed using marker coordinates at the end of isovolumic relaxation (IVR, when pressure difference across the valve is approximately zero), as the stress-free reference state. Leaflet displacements were simulated during IVR using measured left ventricular and atrial pressures. The elastic moduli in both the commisure-commisure (Ecirc) and radial (Erad) directions were optimized using the Method of Feasible Directions to minimize the difference between simulated and measured displacements. The derived material properties were found to be orders of magnitude greater than previously determined ex vivo material properties. Histologic studies have shown that the mitral leaflets, rather than being simple collagen flaps (as once thought), contain complex networks of contractile elements (smooth and striated muscle; valvular interstitial cells), blood vessels, and both afferent & efferent nerves. The finding of higher stiffness in vivo than ex vivo suggests a mechanistic role for these elements; to modulate the stiffness of the active mitral valve in vivo -- a property necessarily missing in excised, flaccid valves ex vivo. Using the derived material properties, a forward analysis was performed to determine the stress-strain behavior of the anterior leaflet at various trans-mitral pressure gradients during IVR. This analysis showed that the leaflet material behaved linearly over a physiologic range of pressures. It is also shown in this thesis that these leaflet material properties vary over the cardiac cycle; leaflet stiffness is higher during early systole (Isovolumic Contraction, IVC) most likely due to force development in cardiac muscle cells in the annular third of the anterior leaflet, and as this force development wanes during systole, the stiffness of the leaflet drops. Stimulation of the neutrally-rich annular saddlehorn region adjacent to the anterior leaflet was shown to almost double leaflet stiffness, whereas administration of a beta-blocker (Esmolol) eliminated the early systolic increase in anterior leaflet stiffness. The initial homogeneous finite element model of the anterior leaflet was further developed to incorporate regionally varying material properties. This heterogeneous finite element model confirmed that Esmolol selectively reduced leaflet stiffness in the annular region (which contains the slip of cardiac muscle) during IVC and did not affect edge stiffness (which is devoid of cardiac muscle). Saddlehorn stimulation caused an increase in leaflet stiffness values for all regions (edge, belly and annular regions) during both IVC and IVR. Loss of atrial contraction had a similar effect on the anterior leaflet as administration of Esmolol, i.e. without atrial depolarization the leaflet stiffness during IVC in the annular region dropped to baseline IVR values. Finally, the functional role of autonomic nerves in the anterior leaflet was investigated by remote stimulation of the vagus nerve. This study showed that vagal nerve stimulation can result in a decrease in anterior leaflet stiffness during both IVR and IVC. In summary, the findings of this thesis suggest a permanent paradigm shift from one viewing the mitral valve leaflets as passive flaps to one viewing the leaflets as active, potentially adaptive, neurally-controlled tissues whose complex function and dysfunction must be taken into account when considering not only therapeutic approaches to mitral valve disease, but even the definitions of mitral valve disease itself. The improved understanding of the structure-function relationships in these native, active valves could uncover new targets for pharmacologic intervention, as well as provide important insights to improve the future design and durability of tissue-engineered mitral valves.
Book Synopsis Solving Nonlinear Equations with Newton's Method by : C. T. Kelley
Download or read book Solving Nonlinear Equations with Newton's Method written by C. T. Kelley and published by SIAM. This book was released on 2003-01-01 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book on Newton's method is a user-oriented guide to algorithms and implementation. In just over 100 pages, it shows, via algorithms in pseudocode, in MATLAB, and with several examples, how one can choose an appropriate Newton-type method for a given problem, diagnose problems, and write an efficient solver or apply one written by others. It contains trouble-shooting guides to the major algorithms, their most common failure modes, and the likely causes of failure. It also includes many worked-out examples (available on the SIAM website) in pseudocode and a collection of MATLAB codes, allowing readers to experiment with the algorithms easily and implement them in other languages.
Book Synopsis Simulations in Biomedicine V by : Z. M. Arnez
Download or read book Simulations in Biomedicine V written by Z. M. Arnez and published by WIT Press. This book was released on 2003-03-11 with total page 545 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computer models have become increasingly successful in simulating biological phenomena. The advantages of this approach are numerous, particularly in biomedicine where it has led to a better understanding of the mechanics of physiological processes. The use of computational models has also spread to many applications in medicine, as demonstrated by the contents of this volume. Containing papers presented at the Fifth International Conference on Computer Simulations in Biomedicine, the book covers a broad spectrum of topics on applications in this area. The contributions featured are arranged in sections according to their medical and biological perspective in order to make the contents more accessible to medical professionals. Over 50 papers are included and these are divided under the general headings: Simulation of Physiological Processes; Cardiovascular System (Vascular System; Lung; Cardiac; Applications); Artificial Limbs & Joints – Orthopaedics & Biomechanics; Electrical Stimulation (Functional Electrical Stimulation; Cellular Engineering); Data Acquisition & Computer Vision – Analysis & Diagnostics; Applications of Artificial Intelligence in Medicine; and Virtual & Intelligent Environments.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1995 with total page 742 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Cardiovascular Mechanics by : Michel R. Labrosse
Download or read book Cardiovascular Mechanics written by Michel R. Labrosse and published by CRC Press. This book was released on 2018-09-13 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this book is to illustrate in specific detail how cardiovascular mechanics stands as a common pillar supporting such different clinical successes as drugs for high blood pressure, prosthetic heart valves and coronary artery bypass grafting, among others. This information is conveyed through a comprehensive treatment of the overarching principles and theories that are behind mechanobiological processes, aortic and arterial mechanics, atherosclerosis, blood and microcirculation, hear valve mechanics, as well as medical devices and drugs. Examines all major theoretical and practical aspects of mechanical forces related to the cardiovascular system. Discusses a unique coverage of mechanical changes related to an aging cardiovascular system. Provides an overview of experimental methods in cardiovascular mechanics. Written by world-class researchers from Canada, the US and EU. Extensive references are provided at the end of each chapter to enhance further study. Michel R. Labrosse is the founder of the Cardiovascular Mechanics Laboratory at the University of Ottawa, where he is a full professor within the Department of Mechanical Engineering. He has been an active researcher in academia along with being heavily associated with the University of Ottawa Heart Institute. He has authored or co-authored over 90 refereed communications, and supervised or co-supervised over 40 graduate students and post-docs.
Book Synopsis Fast Radial Basis Functions for Engineering Applications by : Marco Evangelos Biancolini
Download or read book Fast Radial Basis Functions for Engineering Applications written by Marco Evangelos Biancolini and published by Springer. This book was released on 2018-03-29 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the first “How To” guide to the use of radial basis functions (RBF). It provides a clear vision of their potential, an overview of ready-for-use computational tools and precise guidelines to implement new engineering applications of RBF. Radial basis functions (RBF) are a mathematical tool mature enough for useful engineering applications. Their mathematical foundation is well established and the tool has proven to be effective in many fields, as the mathematical framework can be adapted in several ways. A candidate application can be faced considering the features of RBF: multidimensional space (including 2D and 3D), numerous radial functions available, global and compact support, interpolation/regression. This great flexibility makes RBF attractive – and their great potential has only been partially discovered. This is because of the difficulty in taking a first step toward RBF as they are not commonly part of engineers’ cultural background, but also due to the numerical complexity of RBF problems that scales up very quickly with the number of RBF centers. Fast RBF algorithms are available to alleviate this and high-performance computing (HPC) can provide further aid. Nevertheless, a consolidated tradition in using RBF in engineering applications is still missing and the beginner can be confused by the literature, which in many cases is presented with language and symbolisms familiar to mathematicians but which can be cryptic for engineers. The book is divided in two main sections. The first covers the foundations of RBF, the tools available for their quick implementation and guidelines for facing new challenges; the second part is a collection of practical RBF applications in engineering, covering several topics, including response surface interpolation in n-dimensional spaces, mapping of magnetic loads, mapping of pressure loads, up-scaling of flow fields, stress/strain analysis by experimental displacement fields, implicit surfaces, mesh to cad deformation, mesh morphing for crack propagation in 3D, ice and snow accretion using computational fluid dynamics (CFD) data, shape optimization for external aerodynamics, and use of adjoint data for surface sculpting. For each application, the complete path is clearly and consistently exposed using the systematic approach defined in the first section.
Book Synopsis 3D Echocardiography by : Takahiro Shiota
Download or read book 3D Echocardiography written by Takahiro Shiota and published by CRC Press. This book was released on 2020-12-29 with total page 621 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the publication of the second edition of this volume, 3D echocardiography has penetrated the clinical arena and become an indispensable tool for patient care. The previous edition, which was highly commended at the British Medical Book Awards, has been updated with recent publications and improved images. This third edition has added important new topics such as 3D Printing, Surgical and Transcatheter Management, Artificial Valves, and Infective Endocarditis. The book begins by describing the principles of 3D echocardiography, then proceeds to discuss its application to the imaging of • Left and Right Ventricle, Stress Echocardiography • Left Atrium, Hypertrophic Cardiomyopathy • Mitral Regurgitation with Surgical and Nonsurgical Procedures • Mitral Stenosis and Percutaneous Mitral Valvuloplasty • Aortic Stenosis with TAVI / TAVR • Aortic and Tricuspid Regurgitation • Adult Congenital Heart Disease, Aorta • Speckle Tracking, Cardiac Masses, Atrial Fibrillation KEY FEATURES In-depth clinical experiences of the use of 3D/2D echo by world experts Latest findings to demonstrate clinical values of 3D over 2D echo One-click view of 263 innovative videos and 352 high-resolution 3D/2D color images in a supplemental eBook.
Book Synopsis Numerical Analysis of Cardiac Intramural Valve Stress-strain Behavior and Unsteady Blood Flow in the Aortic Valve Leaflet by : Sobhi Nemer Sauob
Download or read book Numerical Analysis of Cardiac Intramural Valve Stress-strain Behavior and Unsteady Blood Flow in the Aortic Valve Leaflet written by Sobhi Nemer Sauob and published by . This book was released on 1996 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Kaplan's Cardiac Anesthesia E-Book by : Joel A. Kaplan
Download or read book Kaplan's Cardiac Anesthesia E-Book written by Joel A. Kaplan and published by Elsevier Health Sciences. This book was released on 2016-10-20 with total page 1280 pages. Available in PDF, EPUB and Kindle. Book excerpt: Now in a revised and expanded 7th Edition, Kaplan’s Cardiac Anesthesia helps you optimize perioperative outcomes for patients undergoing both cardiac and noncardiac surgery. Dr. Joel L. Kaplan, along with associate editors, Drs. John G. T. Augoustides, David L. Reich, and Gerard R. Manecke, guide you through today’s clinical challenges, including the newest approaches to perioperative assessment and management, state-of-the art diagnostic techniques, and cardiovascular and coronary physiology. Complete coverage of echocardiography and current monitoring techniques. Guidance from today’s leaders in cardiac anesthesia, helping you avoid complications and ensure maximum patient safety. More than 800 full-color illustrations. A new section on anesthetic management of the cardiac patient undergoing noncardiac surgery. New availability as an eBook download for use the in OR. Online-only features, including quarterly updates, an ECG atlas...an increased number of videos, including 2-D and 3-D TEE techniques in real time...and an Annual Year End Highlight from the Journal of Cardiovascular Anesthesia that’s posted each February.
Book Synopsis Advances in Hemodynamics and Hemorheology, Volume 1 by : T.V. How
Download or read book Advances in Hemodynamics and Hemorheology, Volume 1 written by T.V. How and published by Elsevier. This book was released on 1996-09-24 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: This series presents reviews covering all aspects of haemodynamics and haemorheology. Topics covered include the complexities of microcirculation, the rheology of blood and blood vessels, and the mechanics of blood flow in arteries and veins. The contributions aim to reflect the advances being made in experimental techniques and instrumentation for laboratory and clinical measurements and in numerical and mathematical modelling. Emphasis is placed on the scientific and engineering principles involved, but particular attention is also given to the clinical significance of this area of research. Topics covered by this volume include viscoelastic properties of blood and blood analogues; blood flow through narrow tubes; and numerical modelling of blood flow.
Book Synopsis Image-based Cfd Simulation of Blood Flow in the Left Ventricle Via Echocardiography Data in a Fluid-structure Interaction (fsi) Framework by : Mohammad Mehri
Download or read book Image-based Cfd Simulation of Blood Flow in the Left Ventricle Via Echocardiography Data in a Fluid-structure Interaction (fsi) Framework written by Mohammad Mehri and published by . This book was released on 2021 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intraventricular flow field is a significant indicator of heart performance. Investigations through blood flow patterns during cardiac cycle, have shown meaningful link between cardiac abnormalities and intraventricular flow. Therefore, in recent years, many researchers have developed methods and techniques for elucidating intraventricular hemodynamics. In this study an image-based framework for simulation of blood flow in the left ventricle (LV) of small animal is introduced based on echocardiographic (echo) data. Anatomical data are extracted from echo images in a step-by-step procedure for geometry construction and transient model development purposes. Regarding inherent noises in echo data which complicates the segmentation process, appropriate filtration and smoothing methods are discussed. As the mouse heart is a widespread model for human heart studies, visualization and investigation of the mouse LV flow can be a great contribution in elucidating the differences between human and mouse heart as well as the similarities between the two. In this study, frameworks for developing 2D and 3D models of LV flow is introduced based on different available echo data of the mouse heart. Formation and evolution of vortical structures along with other insightful hemodynamical features of blood flow in mouse LV is investigated and effect of Mitral valve (MV) leaflets on these features is discussed.
Book Synopsis Numerical Simulation of the Leaflet Designs to Improve Hemodynamics of Mechanical Heart Valves by : Omid Sirous
Download or read book Numerical Simulation of the Leaflet Designs to Improve Hemodynamics of Mechanical Heart Valves written by Omid Sirous and published by . This book was released on 2017 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanical heart valves (MHVs) are widely implanted due to their reliability and long life span. However, patients who receive MHV implants are required and prescribed anticoagulant medication to reduce the high risk of thromboembolic complications. Although MHVs are considered as a long-term devices to save the lives of thousands of patients suffering from severe heart valve diseases, current designs could be improved based on the fundamentals of fluid mechanics in order to overcome some of the serious complications that can threaten the lives of patients, as well as improve the quality of their lives. Non-physiological blood flow and a higher level of mechanical stresses endured by the blood cells are considered as possible elements of those complications. It is believed that due to the non-physiological blood flow field through the MHVs, leaflet(s) motion can induce thromboembolism and also embolic strokes. The influence of higher levels of mechanical shear stresses, exposure time, and static flow zones behind the leaflet(s) cause significant effects to elevate platelet activation and thromboembolism formation. This research is an effort to provide further information regarding the capability of the passive flow management techniques to reduce these complications, and therefore improve the hemodynamic characteristics of blood flow to prevent high shear stress zones and blood cell damage. The objective of the current research activities is an attempt to examine pulsatile blood flow through MHVs with modified designs. In this investigation, we aim to investigate the effect of the valves with porous leaflets and compare the proposed design with the basic leaflet design. A set of steady and transient 3-dimensional models of MHVs with pulsatile, non-Newtonian turbulent blood flow were developed and investigated in order to: (1) numerically analyze the result of passive flow control techniques, (2) improve the hemodynamics of the valve, and (3) reduce the excessive levels of mechanical stresses compared to the basic bileaflet MHV. The computational models show a distinct difference in the flow field in the two designs, both of which demonstrate significant improvements in the hemodynamics of MHV.
