Cardiac Mechanics and Function in the Normal and Diseased Heart


Book Description

Cardiovascular dynamics is a field in which modelling and systems analysis have formed an extremely important discipline. For example, understanding of even such a fundamental function of the circulation as the relationship between central venous pressure apd cardiac output has required evolution of a pertinent model based on years of exhaustive ex perimental investigations by Starling, Starr, and Guyton. Hemodynamic analyses of pulsatile pressures and flows in the arteries and veins have been a continuing challenge taken up by champions of fluid dynamics such as Frank, Wetterer, Taylor, and Wormersley, just to mention a few names, and some kind of model was always proposed as a conceptual framework. An even greater challenge to cardiovascular dynamicists was how to analyze the intermittent coupling of the ventricle and the arterial or venous vasculature through the valve. The availability of numerical solutions by computer and the recently evolved ventricular model with a time-varying elastance and a pressure-dependent internal resistance opened the way to analysis of this coupling. The ever increasing speed of computers has also facilitated trips between the fre quency and the time domain, even on-line for some experimental studies. This book contains many analyses dedicated to the interactions between the heart and the vasculature, providing the reader with findings at the cutting edge of current research in this field.




Theory of Heart


Book Description

In recent years there has been a growth in interest in studying the heart from the perspective of the physical sciences: mechanics, fluid flow, electromechanics. This volume is the result of a workshop held in July 1989 at the Institute for Nonlinear Sciences at the University of California at San Diego that brought together scientists and clinicians with graduate students and postdoctoral fellows who shared an interest in the heart. The chapters were prepared by the invited speakers as didactic reviews of their subjects but also include the structure, mechanical properties, and function of the heart and the myocardium, electrical activity of the heart and myocardium, and mathematical models of heart function.




Regulation of Cardiac Contractility


Book Description

Contractility describes the relative ability of the heart to eject a stroke volume (SV) at a given prevailing afterload (arterial pressure) and preload (end-diastolic volume; EDV). Various measures of contractility are related to the fraction as the SV/EDV or the ejection fraction, and the dynamics of ejection as determined from maximum pressure rise in the ventricles or arteries or from aortic flow velocities determined by echocardiography. At the cellular level, the ultimate determinant of contractility is the relative tension generation and shortening capability of the molecular motors (myosin cross-bridges) of the sarcomeres as determined by the rates and extent of Ca activation, the turnover kinetics of the cross-bridges, and the relative Ca responsiveness of the sarcomeres. Engagement of the regulatory signaling cascades controlling contractility occurs with occupancy and signal transduction by receptors for neurohumors of the autonomic nervous system as well as growth and stress signaling pathways. Contractility is also determined by the prevailing conditions of pH, temperature, and redox state. Short-term control of contractility is fully expressed during exercise. In long-term responses to stresses on the heart, contractility is modified by cellular remodeling and altered signaling that may compensate for a time but which ultimately may fail, leading to disorders.




Ventricular Mechanics in Congenital Heart Disease


Book Description

Looking at "Horse in Motion", the iconic photograph by E. Muybridge, it is almost possible to hear the horse galloping. The pounding sound of the hoofs hitting the ground -like a drum- can also echo the rythmic beating of the human heart. That sound, that visceral rhythm, reminds us of the link between motion and performance: the perfectly executed stride of the horse, the incredible coordination of multiscale phenomena behind a heart beat. Furthermore, the decomposed sequence in Muybridge's photograph has become a well-known example of breaking motion into its components over time, and as such is reminiscent of those images that are routinely acquired in clinical practice, where the heart appears dilating and shirnking in a sequence of snapshots. The investigation of this motion and its subtleties is essential for refining our understanding of cardiac function, and the appreciation of how and when this motion is no longer perfectly executed can lead us to understand functional impairments and provide insight into the unfolding of pathology. In the presence of congenital heart disease (CHD), cardiac mechanics are altered: from single ventricle physiology to conduction abnormalities to different cardiomyopathies, it is important to both capture and interpret biomechanical changes that occur in the presence of a congenital defect. This special issue in Frontiers in Pediatrics, now an e-book, focuses on 'Ventricular mechanics in congenital heart disease' and looks at current knowledge of phenomena such as systolic/diastolic dysfuction and current methods (chiefly in cardiovascular magnetic resonance imaging and echocardiography) to evaluate cardiac function in the presence of CHD, and then presents a series of original studies that employ both medical imaging and computational modelling techniques to study specific CHD scenarios.




Regulation of Cardiac Function


Book Description

This book gives a consensus of views and research trends in the regulation of cardiac function and metabolism. Emphasis is given to the elucidation of fundamental concepts and principles of clinically relevant issues. The aim is that the clinician should be able to approach a particular aspect of any given problem logically, thereby gaining insights into the fundamental pathophysiological mechanism underlying diseases states. Regulation of Cardiac Function is organized within six principle areas from the molecular and cellular aspects to more clinically applied problems of heart disease. This book gives pertinent guidelines and summarizes knowledge on basic research relevant to cardiac function and metabolism in health and disease.




Physiology of the Heart


Book Description

The Third Edition of this classic cardiac physiology text emphasizes the interrelationships of basic processes among cells, cardiac muscle function and the biophysics of contractile and electrical behavior. This edition of the critically acclaimed overview of cardiac function in health and disease has been revised to incorporate significant new concepts, expanded chapters on the ischemic heart and heart failure, and a revised illustration program. This book is a critical resource for cardiac physiology students, teachers, clinicians, and investigators.




Cardiovascular Biomechanics


Book Description

This book provides a balanced presentation of the fundamental principles of cardiovascular biomechanics research, as well as its valuable clinical applications. Pursuing an integrated approach at the interface of the life sciences, physics and engineering, it also includes extensive images to explain the concepts discussed. With a focus on explaining the underlying principles, this book examines the physiology and mechanics of circulation, mechanobiology and the biomechanics of different components of the cardiovascular system, in-vivo techniques, in-vitro techniques, and the medical applications of this research. Written for undergraduate and postgraduate students and including sample problems at the end of each chapter, this interdisciplinary text provides an essential introduction to the topic. It is also an ideal reference text for researchers and clinical practitioners, and will benefit a wide range of students and researchers including engineers, physicists, biologists and clinicians who are interested in the area of cardiovascular biomechanics.




Mechanics and Energetics of the Myocardium


Book Description

During several decades of this century, the classical physiological studies on the cardiovascular system have greatly improved our knowledge on the function of this system under normal and pathological conditions. This knowledge was the basis of the breakthrough for diagnostic techniques like the Swan-Ganz catheter, coronary arteriography, left and right heart biopsies, and invasive measurements of contractility, as well as therapeutic tools including aortocoronary bypass surgery, percutanous transluminal coronary angioplasty, and a broad field of pharmacological interventions for the whole spectrum of cardiovascular diseases, especially chronic heart failure. It was during the last decade that the scientific world focused on the evolution of molecular biology of the cardiovascular system so that cardiovascular physiology seemed to become less important. Regarding the myocardium, molecular alterations of important functional proteins (phenotype changes), as well as signal transduction pathways of contractility and cardiac growth have been elucidated. The functional importance of a number of genes has undoubtedly been proven with the help of transgenic animals. Mechanics and Energetics of the Myocardium provides an overview for those researchers and practioners interested in the broad field of molecular biology and physiology of the cardiovascular system.




Myocardial torsion


Book Description

Myocardial Torsion is a book different from others, simply because this book is unique, unusual, and I dare say with admiration, it is a curious book, partly magical, full of personality, for initiatory readers, revealing, provocative, challenging. The book has the infrequent peculiarity of being based, to a great extent, on original personal and multidisciplinary investigations, granting it an important extra value. The authors define their purpose since the firsts pages of the book: to provide solidity, validity and even more to Torrent Guasp's concepts. This is certainly a different book in its structure, content and elaboration. It is a text that the reader may admire or criticize, that may create skepticism or surprise at the new data it propose, but wich undoudtedly will leavenobody indifferent, and that is something few books can achieve.




Handbook of Cardiac Anatomy, Physiology, and Devices


Book Description

A revolution began in my professional career and education in 1997. In that year, I visited the University of Minnesota to discuss collaborative opportunities in cardiac anatomy, physiology, and medical device testing. The meeting was with a faculty member of the Department of Anesthesiology, Professor Paul Iaizzo. I didn’t know what to expect but, as always, I remained open minded and optimistic. Little did I know that my life would never be the same. . . . During the mid to late 1990s, Paul Iaizzo and his team were performing anesthesia research on isolated guinea pig hearts. We found the work appealing, but it was unclear how this research might apply to our interest in tools to aid in the design of implantable devices for the cardiovascular system. As discussions progressed, we noted that we would be far more interested in reanimation of large mammalian hearts, in particular, human hearts. Paul was confident this could be accomplished on large hearts, but thought that it would be unlikely that we would ever have access to human hearts for this application. We shook hands and the collaboration was born in 1997. In the same year, Paul and the research team at the University of Minnesota (including Bill Gallagher and Charles Soule) reanimated several swine hearts. Unlike the previous work on guinea pig hearts which were reanimated in Langendorff mode, the intention of this research was to produce a fully functional working heart model for device testing and cardiac research.