Download or read book Multiscale Modeling of the Ventricles written by David Urs Josef Keller and published by KIT Scientific Publishing. This book was released on 2014-08-22 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is focused on different aspects within the loop of multiscale modeling: On the cellular level, effects of adrenergic regulation and the Long-QT syndrome have been investigated.On the organ level, a model for the excitation conduction system was developed and the role of electrophysiological heterogeneities was analyzed.On the torso level a dynamic model of a deforming heart was created and the effects of tissue conductivities on the solution of the forward problem were evaluated

Download or read book Multiscale Modeling of the Ventricles From Cellular Electrophysiology to Body Surface Electrocardiograms written by David Urs Josef Keller and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of Multiscale Modeling Methods for Clinical Decision Making in Single Ventricle Heart Patients written by Mahdi Esmaily-Moghadam and published by . This book was released on 2014 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Infants with single ventricle physiology generally undergo three palliative surgeries starting with stage-one, in which a systemic-to-pulmonary connection is established via a shunt. Mortality is the highest among stage-one patients (up to 23%) due to sub-optimal oxygen delivery, ventricle volume overload, myocardial ischemia, and high risk of shunt blockage. The clinical objective of the present study is to simulate the stage-one circulation, analyze possible surgical options, optimize current surgical methods, and explore a novel alternative surgical option. Simulating the stage-one circulation in single ventricle repair requires a set of numerical tools that are developed in the first part of this dissertation. First, an implicit and modular multidomain framework with excellent stability and convergence properties is introduced that allows multiscale simulation of the circulatory system. Second, a stabilized formulation is presented for treating backflow at Neumann boundaries that is inexpensive, stable, simple, and minimally intrusive, and offers a promising alternative to previous methods. Third, an efficient pre-conditioner for coupled boundary conditions and an efficient iterative algorithm for solving system of equations governing incompressible flows are introduced. Fourth, a scalable parallel data structure is introduced for performing algebraic operations in iterative solvers efficiently. Fifth, an Eulerian formulation is proposed for calculating residence time that lacks mesh dependency and avoids the high computational cost of Lagrangian particle-based approaches. These tools are applicable to other cardiac mechanics and CFD simulations as well. In second part of this dissertation, single ventricle physiology is studied using the tools presented in the first part. First, a multiscale model of single ventricle physiology is simulated and the shunt geometry is optimized to maximize oxygen delivery and improve performance. Second, surgical scenarios single and multiple systemic-to-pulmonary connections are compared, revealing higher thrombotic risk and lower oxygen delivery in the presence of multiple connections. Third, a novel stage one palliative surgery, which provides an alternative source of blood flow in case of shunt blockage and may ultimately reduce the number of open chest surgeries from three to two, is proposed and tested using multiscale modeling. Results reveal the proposed surgical method, the Assisted Bidirectional Glenn, can deliver more oxygen at a reduced heart load with only a modest increase in venous return pressure.

Download or read book Multiscale Modeling of Cardiac Electrophysiology Adaptation to Atrial and Ventricular Rhythm Disorders and Pharmacological Treatment written by Mathias Wilhelms and published by KIT Scientific Publishing. This book was released on 2014-05-22 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiscale modeling of cardiac electrophysiology helps to better understand the underlying mechanisms of atrial fibrillation, acute cardiac ischemia and pharmacological treatment. For this purpose, measurement data reflecting these conditions have to be integrated into models of cardiac electrophysiology. Several methods for this model adaptation are introduced in this thesis. The resulting effects are investigated in multiscale simulations ranging from the ion channel up to the body surface.AbstractEnglisch = Multiscale modeling of cardiac electrophysiology helps to better understand the underlying mechanisms of atrial fibrillation, acute cardiac ischemia and pharmacological treatment. For this purpose, measurement data reflecting these conditions have to be integrated into models of cardiac electrophysiology. Several methods for this model adaptation are introduced in this thesis. The resulting effects are investigated in multiscale simulations ranging from the ion channel up to the body surface.

Download or read book Multiscale Biomechanical Modeling of the Brain written by Mark F. Horstemeyer and published by Academic Press. This book was released on 2021-10-27 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiscale Biomechanical Modeling of the Brain discusses the constitutive modeling of the brain at various length scales (nanoscale, microscale, mesoscale, macroscale and structural scale). In each scale, the book describes the state-of-the- experimental and computational tools used to quantify critical deformational information at each length scale. Then, at the structural scale, several user-based constitutive material models are presented, along with real-world boundary value problems. Lastly, design and optimization concepts are presented for use in occupant-centric design frameworks. This book is useful for both academia and industry applications that cover basic science aspects or applied research in head and brain protection.The multiscale approach to this topic is unique, and not found in other books. It includes meticulously selected materials that aim to connect the mechanistic analysis of the brain tissue at size scales ranging from subcellular to organ levels. Presents concepts in a theoretical and thermodynamic framework for each length scale Teaches readers not only how to use an existing multiscale model for each brain but also how to develop a new multiscale model Takes an integrated experimental-computational approach and gives structured multiscale coverage of the problems

Download or read book Toward Real time Modeling of Human Heart Ventricles at Cellular Resolution written by and published by . This book was released on 2012 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computational Modeling and Simulation Examples in Bioengineering written by Nenad Filipovic and published by John Wiley & Sons. This book was released on 2021-12-14 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: A systematic overview of the quickly developing field of bioengineering—with state-of-the-art modeling software! Computational Modeling and Simulation Examples in Bioengineering provides a comprehensive introduction to the emerging field of bioengineering. It provides the theoretical background necessary to simulating pathological conditions in the bones, muscles, cardiovascular tissue, and cancers, as well as lung and vertigo disease. The methodological approaches used for simulations include the finite element, dissipative particle dynamics, and lattice Boltzman. The text includes access to a state-of-the-art software package for simulating the theoretical problems. In this way, the book enhances the reader's learning capabilities in the field of biomedical engineering. The aim of this book is to provide concrete examples of applied modeling in biomedical engineering. Examples in a wide range of areas equip the reader with a foundation of knowledge regarding which problems can be modeled with which numerical methods. With more practical examples and more online software support than any competing text, this book organizes the field of computational bioengineering into an accessible and thorough introduction. Computational Modeling and Simulation Examples in Bioengineering: Includes a state-of-the-art software package enabling readers to engage in hands-on modeling of the examples in the book Provides a background on continuum and discrete modeling, along with equations and derivations for three key numerical methods Considers examples in the modeling of bones, skeletal muscles, cartilage, tissue engineering, blood flow, plaque, and more Explores stent deployment modeling as well as stent design and optimization techniques Generates different examples of fracture fixation with respect to the advantages in medical practice applications Computational Modeling and Simulation Examples in Bioengineering is an excellent textbook for students of bioengineering, as well as a support for basic and clinical research. Medical doctors and other clinical professionals will also benefit from this resource and guide to the latest modeling techniques.

Download or read book Multiscale Modelling of Rhythm Pattern and Information Generation from Genome to Physiome written by Shangbin Chen and published by Frontiers Media SA. This book was released on 2020-06-08 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Multi scale Finite Element Model of the Cardiac Ventricles written by Dimitri Deserranno and published by . This book was released on 2006 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Multiscale Modelling of the Cardiac Specialized Conduction System written by Rafel Bodras and published by . This book was released on 2011 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Death due to lethal cardiac arrhythmias is the leading cause of mortality in Western society. Many of the fundamental mechanisms underlying the onset of arrthythmias, their maintenance and termination, still remain poorly understood. The specialized conduction (or His-Purkinje) system is fundamental to ventricular electrophysiological function and is a key player in various cardiac diseases. In recent years, computational simulation has become an important tool in im- proving our understanding ofthese mechanisms. Current state-of-the-art computational ventric- ular electrophysiology models often do not feature a detailed representation of the specialized conduction system. Ventricular models that do incorporate the specialized conduction system often use a simplified anatomical description and are commonly based on the monodomain equations, rather than the more general bidomain equations. Thus, using computational simula- tion to investigate both normal physiological function of the specialized conduction system and pathologies in which it is involved presents difficulties. This thesis develops the techniques and tools required to model the specialized conduction sys- tem at the ventricular scale. We derive one-dimensional bidomain equations that model elec- trical propagation in the system by reducing the equations associated with a three-dimensional fibre. To complement the derived equations, we develop a numerical solution scheme for the model that is efficient enough to allow ventricular simulations. The one-dimensional bido- main model allows defibrillation studies to be performed with the specialized conduction sys- tem. Secondly, we investigate the imaging and mesh generation tools required to integrate an anatomically detailed mesh of the specialized conduction system into a current state-of-the-art ventricular mesh. Using these tools, a highly detailed rabbit-specific specialized conduction system anatomical model is developed. Simulations are performed that dem~strate the re- sponse of the specialized conduction system to defibrillation strength shocks and we compare activation sequences generated using the model to experimental recordings. Finally, we investi- gate variability in the anatomy of the system. The tools and ventricular model presented in this thesis fulfil an important role in allowing the study of the e1ectrophysiological function of the specialized conduction system at the ventricular scale.

Download or read book Multi organ Finite Element Modeling of the Human Heart with Ventricular arterial Interactions written by Sheikh Mohammad Shavik and published by . This book was released on 2019 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computer heart models with realistic description of cardiac geometry and muscle architecture have advanced significantly over the years. Despite these significant advancements, there are nevertheless, some unresolved issues and aspects that need improvements. The goal of this dissertation was to address some of those issues as well as to develop new computational modeling framework to understand the underlying mechanics in heart failure with preserved ejection fraction (HFpEF) and pulmonary arterial hypertension (PAH). Clinical studies have found that global longitudinal strain is reduced in HFpEF, suggesting that LV contractility is impaired in this syndrome. This finding is, however, contradicted and confounded, respectively, by findings that end-systolic elastance (Ees) and systolic blood pressure (SBP) are typically also increased in HFpEF. To reconcile these issues, we developed and validated a multiscale computational modeling framework consisting of detailed cell‐based descriptors of the cross‐bridge cycling against well‐established organ‐level physiological behaviors. This framework is then used to isolate the effects of HFpEF features in affecting systolic function metrics by quantifying the effects on Ees and myocardial strains due to 1) changes in LV geometry found in HFpEF patients, 2) active tension developed by the tissue (Tref), and 3) afterload. Our study suggests that it is likely that the LV contractility as indexed by the tissue's active tension is reduced in HFpEF patients. Right ventricular assist device (RVAD) has been considered as a treatment option for the end-stage pulmonary arterial hypertension (PAH) patients, but, its effects on biventricular mechanics are, however, largely unknown. To address this issue, we developed an image-based modeling framework consisting of a biventricular finite element (FE) model that is coupled to a lumped model describing the pulmonary and systemic circulations in a closed-loop system. Our results showed that RVAD unloads the RV, improves cardiac output and increases septum curvature, which are more pronounced in the PAH patient with severe RV remodeling. These improvements, however, are also accompanied by an adverse increase in the PA pressure, suggesting that the RVAD implantation may need to be optimized depending on disease progression. While it has long been recognized that bi-directional interaction between the heart and vasculature plays a critical role in the pathophysiological process of HFpEF and PAH, a comprehensive study of this interaction is hampered by a lack of modeling framework capable of simultaneously accommodating high-resolution models of the heart and vasculature. To address this issue, we developed a computational modeling framework that couples FE models of the LV and aorta to simulate ventricular-arterial coupling in the systemic circulation. We show that the model is able to capture the physiological behaviors in both the LV and aorta that are consistent with in vivo measurements. We also showed that the framework can reasonably predict the effects of changes in geometry and microstructural details the two compartments have on each other. The model is extended to accommodate a biventricular FE heart model together with FE models of the aorta and pulmonary artery to simulate the ventricular-vascular interactions in both systemic and pulmonary circulation.

Download or read book Multiscale Modeling of Cardiac Arrhythmogenesis Beyond the Trigger Substrate Paradigm written by Michael B Liu and published by . This book was released on 2019 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Arrhythmias and sudden cardiac death (SCD) represent a leading cause of mortality in the US and worldwide. Currently, the most effective therapy for preventing SCD is the implantable cardioverter-defibrillator (ICD). ICDs however can only terminate arrhythmias after they have already occurred and have numerous severe side effects and poor cost-effectiveness. Therefore, the ideal anti-arrhythmic strategy is the prevention of arrhythmia initiation, or arrhythmogenesis, in the first place. Unfortunately, multiple clinical trials have demonstrated that many of the currently available anti-arrhythmic drugs are not generally effective in the prevention of ventricular arrhythmias, and in some cases may even be pro-arrhythmic unintuitively causing increased mortality. Thus, improved anti-arrhythmic strategies are needed which require improved mechanistic understanding of the arrhythmogenesis process. Computational modeling is a powerful research tool, complementary to experimental and clinical studies, to study the underlying mechanisms of arrhythmias. In this dissertation, we use computer modeling and patch clamp experiments to investigate the spontaneous initiation of triggered and reentrant ventricular arrhythmias as related to delayed afterdepolarizations (DADs) and long QT syndrome (LQTS). We first describe a dynamical threshold for DAD-mediated triggered activity which is lower than the sodium channel threshold and manifests under conditions of hypokalemia and slow spontaneous calcium release. Next, we investigate the critical factors that determine DAD-mediated triggered activity formation in cardiac tissue. Thirdly, we study whether sub-threshold DADs can act as an arrhythmogenic trigger and find that DADs can generate both triggers and a reentry substrate simultaneously. And finally, we detail a novel common mechanism of arrhythmia initiation across different genotypes of LQTS called "R-from-T", which blurs the usual notions between arrhythmia trigger and substrate beyond the traditional paradigm. The mechanistic insights gained from these studies help inform the development of new arrhythmia prevention strategies.

Download or read book Computational Biomechanics for Ventricle arterial Dysfunction and Remodeling in Heart Failure written by and published by Frontiers Media SA. This book was released on 2021-08-24 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cardiac Electrophysiology from Cell to Bedside written by Douglas P. Zipes and published by Elsevier Health Sciences. This book was released on 2013-10-25 with total page 1395 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cardiac Electrophysiology: From Cell to Bedside puts the latest knowledge in this subspecialty at your fingertips, giving you a well-rounded, expert grasp of every cardiac electrophysiology issue that affects your patient management. Drs. Zipes, Jalife, and a host of other world leaders in cardiac electrophysiology use a comprehensive, multidisciplinary approach to guide you through all of the most recent cardiac drugs, techniques, and technologies. Get well-rounded, expert views of every cardiac electrophysiology issue that affects your patient management from preeminent authorities in cardiology, physiology, pharmacology, pediatrics, biophysics, pathology, cardiothoracic surgery, and biomedical engineering from around the world. Visually grasp and easily absorb complex concepts through an attractive full-color design featuring color photos, tables, flow charts, ECGs, and more! Integrate the latest scientific understanding of arrhythmias with the newest clinical applications, to select the right treatment and management options for each patient. Stay current on the latest advancements and developments with sweeping updates and 52 NEW chapters - written by many new authors - on some of the hottest cardiology topics, such as new technologies for the study of the molecular structure of ion channels, molecular genetics, and the development of new imaging, mapping and ablation techniques. Get expert advice from Dr. Douglas P. Zipes - a leading authority in electrophysiology and editor of Braunwald's Heart Disease and the Heart Rhythm Journal - and Dr. Jose Jalife - a world-renowned leader and researcher in basic and translational cardiac electrophysiology. Access the full text online at Expert Consult, including supplemental text, figures, tables, and video clips. Your purchase entitles you to access the web site until the next edition is published, or until the current edition is no longer offered for sale by Elsevier, whichever occurs first. If the next edition is published less than one year after your purchase, you will be entitled to online access for one year from your date of purchase. Elsevier reserves the right to offer a suitable replacement product (such as a downloadable or CD-ROM-based electronic version) should online access to the web site be discontinued.

Download or read book Advanced HPC based Computational Modeling in Biomechanics and Systems Biology written by Mariano Vázquez and published by Frontiers Media SA. This book was released on 2019-04-04 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.

Download or read book Mathematical Modelling in Biomedicine written by Vitaly Volpert and published by MDPI. This book was released on 2021-01-26 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematical modelling in biomedicine is a rapidly developing scientific discipline at the intersection of medicine, biology, mathematics, physics, and computer science. Its progress is stimulated by fundamental scientific questions and by the applications to public health. This book represents a collection of papers devoted to mathematical modelling of various physiological problems in normal and pathological conditions. It covers a broad range of topics including cardiovascular system and diseases, heart and brain modelling, tumor growth, viral infections, and immune response. Computational models of blood circulation are used to study the influence of heart arrhythmias on coronary blood flow and on operating modes for left-ventricle-assisted devices. Wave propagation in the cardiac tissue is investigated in order to show the influence of tissue heterogeneity and fibrosis. The models of tumor growth are used to determine optimal protocols of antiangiogenic and radiotherapy. The models of viral hepatitis kinetics are considered for the parameter identification, and the evolution of viral quasi-species is investigated. The book presents the state-of-the-art in mathematical modelling in biomedicine and opens new perspectives in this passionate field of research.