WorldWideScience

Sample records for cardiac electrophysiology

  1. Electrophysiological Cardiac Modeling: A Review.

    Science.gov (United States)

    Beheshti, Mohammadali; Umapathy, Karthikeyan; Krishnan, Sridhar

    2016-01-01

    Cardiac electrophysiological modeling in conjunction with experimental and clinical findings has contributed to better understanding of electrophysiological phenomena in various species. As our knowledge on underlying electrical, mechanical, and chemical processes has improved over time, mathematical models of the cardiac electrophysiology have become more realistic and detailed. These models have provided a testbed for various hypotheses and conditions that may not be easy to implement experimentally. In addition to the limitations in experimentally validating various scenarios implemented by the models, one of the major obstacles for these models is computational complexity. However, the ever-increasing computational power of supercomputers facilitates the clinical application of cardiac electrophysiological models. The potential clinical applications include testing and predicting effects of pharmaceutical agents and performing patient-specific ablation and defibrillation. A review of studies involving these models and their major findings are provided.

  2. Mathematical cardiac electrophysiology

    CERN Document Server

    Colli Franzone, Piero; Scacchi, Simone

    2014-01-01

    This book covers the main mathematical and numerical models in computational electrocardiology, ranging from microscopic membrane models of cardiac ionic channels to macroscopic bidomain, monodomain, eikonal models and cardiac source representations. These advanced multiscale and nonlinear models describe the cardiac bioelectrical activity from the cell level to the body surface and are employed in both the direct and inverse problems of electrocardiology. The book also covers advanced numerical techniques needed to efficiently carry out large-scale cardiac simulations, including time and space discretizations, decoupling and operator splitting techniques, parallel finite element solvers. These techniques are employed in 3D cardiac simulations illustrating the excitation mechanisms, the anisotropic effects on excitation and repolarization wavefronts, the morphology of electrograms in normal and pathological tissue and some reentry phenomena. The overall aim of the book is to present rigorously the mathematica...

  3. Historical perspectives of cardiac electrophysiology.

    Science.gov (United States)

    Lüderitz, Berndt

    2009-01-01

    The diagnosis and treatment of clinical electrophysiology has a long and fascinating history. From earliest times, no clinical symptom impressed the patient (and the physician) more than an irregular heart beat. Although ancient Chinese pulse theory laid the foundation for the study of arrhythmias and clinical electrophysiology in the 5th century BC, the most significant breakthrough in the identification and treatment of cardiac arrhythmias first occurred in this century. In the last decades, our knowledge of electrophysiology and pharmacology has increased exponentially. The enormous clinical significance of cardiac rhythm disturbances has favored these advances. On the one hand, patients live longer and thus are more likely to experience arrhythmias. On the other hand, circulatory problems of the cardiac vessels have increased enormously, and this has been identified as the primary cause of cardiac rhythm disorders. Coronary heart disease has become not just the most significant disease of all, based on the statistics for cause of death. Arrhythmias are the main complication of ischemic heart disease, and they have been directly linked to the frequently arrhythmogenic sudden death syndrome, which is now presumed to be an avoidable "electrical accident" of the heart. A retrospective look--often charming in its own right--may not only make it easier to sort through the copious details of this field and so become oriented in this universe of important and less important facts: it may also provide the observer with a chronological vantage point from which to view the subject. The study of clinical electrophysiology is no dry compendium of facts and figures, but rather a dynamic field of study evolving out of the competition between various ideas, intentions and theories. PMID:19196616

  4. Molecular and Electrophysiological Mechanisms Underlying Cardiac Arrhythmogenesis in Diabetes Mellitus.

    Science.gov (United States)

    Tse, Gary; Lai, Eric Tsz Him; Tse, Vivian; Yeo, Jie Ming

    2016-01-01

    Diabetes is a common endocrine disorder with an ever increasing prevalence globally, placing significant burdens on our healthcare systems. It is associated with significant cardiovascular morbidities. One of the mechanisms by which it causes death is increasing the risk of cardiac arrhythmias. The aim of this article is to review the cardiac (ion channel abnormalities, electrophysiological and structural remodelling) and extracardiac factors (neural pathway remodelling) responsible for cardiac arrhythmogenesis in diabetes. It is concluded by an outline of molecular targets for future antiarrhythmic therapy for the diabetic population. PMID:27642609

  5. Simulation methods and validation criteria for modeling cardiac ventricular electrophysiology

    OpenAIRE

    Shankarjee Krishnamoorthi; Luigi E Perotti; Nils P Borgstrom; Ajijola, Olujimi A.; Anna Frid; Ponnaluri, Aditya V.; Weiss, James N.; Zhilin Qu; Klug, William S.; Ennis, Daniel B.; Alan Garfinkel

    2014-01-01

    © 2014 Krishnamoorthi et al. We describe a sequence of methods to produce a partial differential equation model of the electrical activation of the ventricles. In our framework, we incorporate the anatomy and cardiac microstructure obtained from magnetic resonance imaging and diffusion tensor imaging of a New Zealand White rabbit, the Purkinje structure and the Purkinje-muscle junctions, and an electrophysiologically accurate model of the ventricular myocytes and tissue, which includes transm...

  6. Minimum Information about a Cardiac Electrophysiology Experiment (MICEE)

    DEFF Research Database (Denmark)

    Quinn, T A; Granite, S; Allessie, M A;

    2011-01-01

    (MICEE). The ultimate goal is to develop a useful tool for cardiac electrophysiologists which facilitates and improves dissemination of the minimum information necessary for reproduction of cardiac electrophysiology research, allowing for easier comparison and utilisation of findings by others....... It is hoped that this will enhance the integration of individual results into experimental, computational, and conceptual models. In its present form, this draft is intended for assessment and development by the research community. We invite the reader to join this effort, and, if deemed productive, implement...

  7. Towards Real-Time Computation of Cardiac Electrophysiology for Training Simulator

    OpenAIRE

    Talbot, Hugo; Duriez, Christian; Courtecuisse, Hadrien; Relan, Jatin; Sermesant, Maxime; Cotin, Stéphane; Delingette, Hervé

    2012-01-01

    This work aims at developing a training simulator for interventional radiology and thermo-ablation of cardiac arrhythmias. To achieve this, a real-time model of the cardiac electrophysiology is needed, which is very challenging due to the stiff equations involved. In this paper, we detail our contributions in order to obtain efficient cardiac electrophysiology simulations. First, an adaptive parametrisation of the Mitchell-Schaeffer model as well as numerical optimizations are proposed. An ac...

  8. Simulation Methods and Validation Criteria for Modeling Cardiac Ventricular Electrophysiology.

    Directory of Open Access Journals (Sweden)

    Shankarjee Krishnamoorthi

    Full Text Available We describe a sequence of methods to produce a partial differential equation model of the electrical activation of the ventricles. In our framework, we incorporate the anatomy and cardiac microstructure obtained from magnetic resonance imaging and diffusion tensor imaging of a New Zealand White rabbit, the Purkinje structure and the Purkinje-muscle junctions, and an electrophysiologically accurate model of the ventricular myocytes and tissue, which includes transmural and apex-to-base gradients of action potential characteristics. We solve the electrophysiology governing equations using the finite element method and compute both a 6-lead precordial electrocardiogram (ECG and the activation wavefronts over time. We are particularly concerned with the validation of the various methods used in our model and, in this regard, propose a series of validation criteria that we consider essential. These include producing a physiologically accurate ECG, a correct ventricular activation sequence, and the inducibility of ventricular fibrillation. Among other components, we conclude that a Purkinje geometry with a high density of Purkinje muscle junctions covering the right and left ventricular endocardial surfaces as well as transmural and apex-to-base gradients in action potential characteristics are necessary to produce ECGs and time activation plots that agree with physiological observations.

  9. Cellular cardiac electrophysiology modelling with Chaste and CellML

    Directory of Open Access Journals (Sweden)

    Jonathan eCooper

    2015-01-01

    Full Text Available Chaste is an open-source C++ library for computational biology that has well-developed cardiac electrophysiology tissue simulation support. In this paper, we introduce the features available for performing cardiac electrophysiology action potential simulations using a wide range of models from the Physiome repository.The mathematics of the models are described in CellML, with units for all quantities. The primary idea is that the model is defined in one place (the CellML file, and all model code is auto-generated at compile or run time; it never has to be manually edited.We use ontological annotation to identify model variables describing certain biological quantities (membrane voltage, capacitance, etc. to allow us to import any relevant CellML models into the Chaste framework in consistent units, and to interact with them via consistent interfaces. This approach provides a great deal of flexibility for analysing different models of the same system. Chaste provides a wide choice of numerical methods for solving the ordinary differential equations that describe the models. Fixed-timestep explicit and implicit solvers are provided, as discussed in previous work. Here we introduce the Rush--Larsen and Generalised Rush--Larsen integration techniques, made available via symbolic manipulation of the model equations, which are automatically rearranged into the forms required by these approaches. We have also integrated the CVODE solvers, a `gold standard' for stiff systems, and we have developed support for symbolic computation of the Jacobian matrix, yielding further increases in the performance and accuracy of CVODE. We discuss some of the technical details of this work and compare the performance of the available numerical methods.Finally, we discuss how this is generalised in our functional curation framework, which uses a domain-specific language for defining complex experiments as a basis for comparison of model behaviour.

  10. Myokit: A simple interface to cardiac cellular electrophysiology.

    Science.gov (United States)

    Clerx, Michael; Collins, Pieter; de Lange, Enno; Volders, Paul G A

    2016-01-01

    Myokit is a new powerful and versatile software tool for modeling and simulation of cardiac cellular electrophysiology. Myokit consists of an easy-to-read modeling language, a graphical user interface, single and multi-cell simulation engines and a library of advanced analysis tools accessible through a Python interface. Models can be loaded from Myokit's native file format or imported from CellML. Model export is provided to C, MATLAB, CellML, CUDA and OpenCL. Patch-clamp data can be imported and used to estimate model parameters. In this paper, we review existing tools to simulate the cardiac cellular action potential to find that current tools do not cater specifically to model development and that there is a gap between easy-to-use but limited software and powerful tools that require strong programming skills from their users. We then describe Myokit's capabilities, focusing on its model description language, simulation engines and import/export facilities in detail. Using three examples, we show how Myokit can be used for clinically relevant investigations, multi-model testing and parameter estimation in Markov models, all with minimal programming effort from the user. This way, Myokit bridges a gap between performance, versatility and user-friendliness.

  11. Myokit: A simple interface to cardiac cellular electrophysiology.

    Science.gov (United States)

    Clerx, Michael; Collins, Pieter; de Lange, Enno; Volders, Paul G A

    2016-01-01

    Myokit is a new powerful and versatile software tool for modeling and simulation of cardiac cellular electrophysiology. Myokit consists of an easy-to-read modeling language, a graphical user interface, single and multi-cell simulation engines and a library of advanced analysis tools accessible through a Python interface. Models can be loaded from Myokit's native file format or imported from CellML. Model export is provided to C, MATLAB, CellML, CUDA and OpenCL. Patch-clamp data can be imported and used to estimate model parameters. In this paper, we review existing tools to simulate the cardiac cellular action potential to find that current tools do not cater specifically to model development and that there is a gap between easy-to-use but limited software and powerful tools that require strong programming skills from their users. We then describe Myokit's capabilities, focusing on its model description language, simulation engines and import/export facilities in detail. Using three examples, we show how Myokit can be used for clinically relevant investigations, multi-model testing and parameter estimation in Markov models, all with minimal programming effort from the user. This way, Myokit bridges a gap between performance, versatility and user-friendliness. PMID:26721671

  12. Cardiac differentiation and electrophysiology characteristics of bone marrow mesenchymal stem cells

    Institute of Scientific and Technical Information of China (English)

    LIU Bo-wu; AI Shi-yi; L(U) An-lin; HOU Jing; HUANG Wei; LI Yao; HOU Zhao-lei; HOU Hong; DA Jing; YANG Na

    2012-01-01

    Objective To review the progress of cardiac differentiation and electrophysiological characteristics of bone marrow mesenchymal stem cells.Data sources The databases of PubMed,Springer Link,Science Direct and CNKI were retrieved for papers published from January 2000 to January 2012 with the key words of “bone marrow mesenchymal stem cells,cardiac or heart,electrophysiology or electrophysiological characteristics”.Study selection The articles concerned cardiac differentiation and electrophysiological characteristics of bone marrow mesenchymal stem cells were collected.After excluding papers that study purposes are not coincident with this review or contents duplicated,56 papers were internalized at last.Results For the treatment of myocardial infarction and myocardiac disease,the therapeutic effects of transplantation of bone marrow mesenchymal stem cells which have the ability to develop into functional myocardial cells by lots of methods have been proved by many researches.But the arrhythmogenic effect on ventricles affer transplantation of bone marrow mesenchymal stem cells derived myocardial cells is still controversial in animal models.Certainly,the low differentiation efficiency and heterogeneous development of electricial function could be the most important risk for proarrhythmia.Conclusion Many studies of cardiac differentiation of bone marrow mesenchymal stem cells have paid attention to improve the cardiac differentiation rate,and the electrophysiology characteristics of the differentiated cells should be concerned for the risk for proarrhythmia as well.

  13. Toward cardiac electrophysiological mapping based on micro-Tesla NMR: a novel modality for localizing the cardiac reentry

    OpenAIRE

    Kiwoong Kim

    2012-01-01

    Matching the proton magnetic resonance frequency to the frequency of a periodic electrophysiological excitation of myocardium enables direct localization of the cardiac reentry by magnetic resonance imaging techniques. The feasibility of this new idea has been demonstrated by conducting a numerical simulation based on a realistic heart model and experimental parameters in SQUID-based micro-Tesla NMR.

  14. Toward cardiac electrophysiological mapping based on micro-Tesla NMR: a novel modality for localizing the cardiac reentry

    Science.gov (United States)

    Kim, Kiwoong

    2012-06-01

    Matching the proton magnetic resonance frequency to the frequency of a periodic electrophysiological excitation of myocardium enables direct localization of the cardiac reentry by magnetic resonance imaging techniques. The feasibility of this new idea has been demonstrated by conducting a numerical simulation based on a realistic heart model and experimental parameters in SQUID-based micro-Tesla NMR.

  15. Myocardial Infarct Segmentation From Magnetic Resonance Images for Personalized Modeling of Cardiac Electrophysiology.

    Science.gov (United States)

    Ukwatta, Eranga; Arevalo, Hermenegild; Li, Kristina; Yuan, Jing; Qiu, Wu; Malamas, Peter; Wu, Katherine C; Trayanova, Natalia A; Vadakkumpadan, Fijoy

    2016-06-01

    Accurate representation of myocardial infarct geometry is crucial to patient-specific computational modeling of the heart in ischemic cardiomyopathy. We have developed a methodology for segmentation of left ventricular (LV) infarct from clinically acquired, two-dimensional (2D), late-gadolinium enhanced cardiac magnetic resonance (LGE-CMR) images, for personalized modeling of ventricular electrophysiology. The infarct segmentation was expressed as a continuous min-cut optimization problem, which was solved using its dual formulation, the continuous max-flow (CMF). The optimization objective comprised of a smoothness term, and a data term that quantified the similarity between image intensity histograms of segmented regions and those of a set of training images. A manual segmentation of the LV myocardium was used to initialize and constrain the developed method. The three-dimensional geometry of infarct was reconstructed from its segmentation using an implicit, shape-based interpolation method. The proposed methodology was extensively evaluated using metrics based on geometry, and outcomes of individualized electrophysiological simulations of cardiac dys(function). Several existing LV infarct segmentation approaches were implemented, and compared with the proposed method. Our results demonstrated that the CMF method was more accurate than the existing approaches in reproducing expert manual LV infarct segmentations, and in electrophysiological simulations. The infarct segmentation method we have developed and comprehensively evaluated in this study constitutes an important step in advancing clinical applications of personalized simulations of cardiac electrophysiology. PMID:26731693

  16. Reduced-order modeling for cardiac electrophysiology. Application to parameter identification

    CERN Document Server

    Boulakia, Muriel; Gerbeau, Jean-Frédéric

    2011-01-01

    A reduced-order model based on Proper Orthogonal Decomposition (POD) is proposed for the bidomain equations of cardiac electrophysiology. Its accuracy is assessed through electrocardiograms in various configurations, including myocardium infarctions and long-time simulations. We show in particular that a restitution curve can efficiently be approximated by this approach. The reduced-order model is then used in an inverse problem solved by an evolutionary algorithm. Some attempts are presented to identify ionic parameters and infarction locations from synthetic ECGs.

  17. Electrophysiologic testing guided risk stratification approach for sudden cardiac death beyond the left ventricular ejection fraction.

    Science.gov (United States)

    Gatzoulis, Konstantinos A; Tsiachris, Dimitris; Arsenos, Petros; Tousoulis, Dimitris

    2016-01-26

    Sudden cardiac death threats ischaemic and dilated cardiomyopathy patients. Anti- arrhythmic protection may be provided to these patients with implanted cardiac defibrillators (ICD), after an efficient risk stratification approach. The proposed risk stratifier of an impaired left ventricular ejection fraction has limited sensitivity meaning that a significant number of victims will remain undetectable by this risk stratification approach because they have a preserved left ventricular systolic function. Current risk stratification strategies focus on combinations of non invasive methods like T wave alternans, late potentials, heart rate turbulence, deceleration capacity and others, with invasive methods like the electrophysiologic study. In the presence of an electrically impaired substrate with formed post myocardial infarction fibrotic zones, programmed ventricular stimulation provides important prognostic information for the selection of the patients expected to benefit from an ICD implantation, while due to its high negative predictive value, patients at low risk level may also be detected. Clustering evidence from different research groups and electrophysiologic labs support an electrophysiologic testing guided risk stratification approach for sudden cardiac death.

  18. Mechanisms of electrical activation and conduction in the gastrointestinal system: lessons from cardiac electrophysiology

    Directory of Open Access Journals (Sweden)

    Gary eTse

    2016-05-01

    Full Text Available The gastrointestinal (GI tract is an electrically excitable organ system containing multiple cell types, which coordinate electrical activity propagating through this tract. Disruption in its normal electrophysiology is observed in a number of GI motility disorders. However, this is not well characterized and the field of GI electrophysiology is much less developed compared to the cardiac field. The aim of this article is to use the established knowledge of cardiac electrophysiology to shed light on the mechanisms of electrical activation and propagation along the GI tract, and how abnormalities in these processes lead to motility disorders and suggest better treatment options based on this improved understanding. In the first part of the article, the ionic contributions to the generation of GI slow wave and the cardiac action potential (AP are reviewed. Propagation of these electrical signals can be described by the core conductor theory in both systems. However, specifically for the GI tract, the following unique properties are observed: changes in slow wave frequency along its length, periods of quiescence, synchronization in short distances and desynchronization over long distances. These are best described by a coupled oscillator theory. Other differences include the diminished role of gap junctions in mediating this conduction in the GI tract compared to the heart. The electrophysiology of conditions such as gastroesophageal reflux disease and gastroparesis, and functional problems such as irritable bowel syndrome are discussed in detail, with reference to ion channel abnormalities and potential therapeutic targets. A deeper understanding of the molecular basis and physiological mechanisms underlying GI motility disorders will enable the development of better diagnostic and therapeutic tools and the advancement of this field.

  19. OptoDyCE: Automated system for high-throughput all-optical dynamic cardiac electrophysiology

    Science.gov (United States)

    Klimas, Aleksandra; Yu, Jinzhu; Ambrosi, Christina M.; Williams, John C.; Bien, Harold; Entcheva, Emilia

    2016-02-01

    In the last two decades, heart's normal electrical function. Consequently, all new drugs must undergo preclinical testing for cardiac liability, adding to an already expensive and lengthy process. Recognition that proarrhythmic effects often result from drug action on multiple ion channels demonstrates a need for integrative and comprehensive measurements. Additionally, patient-specific therapies relying on emerging technologies employing stem-cell derived cardiomyocytes (e.g. induced pluripotent stem-cell-derived cardiomyocytes, iPSC-CMs) require better screening methods to become practical. However, a high-throughput, cost-effective approach for cellular cardiac electrophysiology has not been feasible. Optical techniques for manipulation and recording provide a contactless means of dynamic, high-throughput testing of cells and tissues. Here, we consider the requirements for all-optical electrophysiology for drug testing, and we implement and validate OptoDyCE, a fully automated system for all-optical cardiac electrophysiology. We demonstrate the high-throughput capabilities using multicellular samples in 96-well format by combining optogenetic actuation with simultaneous fast high-resolution optical sensing of voltage or intracellular calcium. The system can also be implemented using iPSC-CMs and other cell-types by delivery of optogenetic drivers, or through the modular use of dedicated light-sensitive somatic cells in conjunction with non-modified cells. OptoDyCE provides a truly modular and dynamic screening system, capable of fully-automated acquisition of high-content information integral for improved discovery and development of new drugs and biologics, as well as providing a means of better understanding of electrical disturbances in the heart.

  20. Automated Electrophysiology Makes the Pace for Cardiac Ion Channel Safety Screening

    Directory of Open Access Journals (Sweden)

    Clemens eMoeller

    2011-11-01

    Full Text Available The field of automated patch-clamp electrophysiology has emerged from the tension between the pharmaceutical industry’s need for high-throughput compound screening versus its need to be conservative due to regulatory requirements. On the one hand, hERG channel screening was increasingly requested for new chemical entities, as the correlation between blockade of the ion channel coded by hERG and Torsades de Pointes cardiac arrhythmia gained increasing attention. On the other hand, manual patch-clamping, typically quoted as the gold-standard for understanding ion channel function and modulation, was far too slow (and, consequently, too expensive for keeping pace with the numbers of compounds submitted for hERG channel investigations from pharmaceutical R&D departments. In consequence it became more common for some pharmaceutical companies to outsource safety pharmacological investigations, with a focus on hERG channel interactions. This outsourcing has allowed those pharmaceutical companies to build up operational flexibility and greater independence from internal resources, and allowed them to obtain access to the latest technological developments that emerged in automated patch-clamp electrophysiology – much of which arose in specialized biotech companies. Assays for nearly all major cardiac ion channels are now available by automated patch-clamping using heterologous expression systems, and recently, automated action potential recordings from stem-cell derived cardiomyocytes have been demonstrated. Today, most of the large pharmaceutical companies have acquired automated electrophysiology robots and have established various automated cardiac ion channel safety screening assays on these, in addition to outsourcing parts of their needs for safety screening.

  1. The pioneering work of George Mines on cardiac arrhythmias: groundbreaking ideas that remain influential in contemporary cardiac electrophysiology.

    Science.gov (United States)

    Aguilar, Martin; Nattel, Stanley

    2016-05-01

    George Mines was a pioneering physiologist who, despite an extremely short period of professional activity and only primitive experimental methodology, succeeded in formulating concepts that continue to be of great influence today. Here, we review some of his most important discoveries and their impact on contemporary concepts and clinical practice. Mines' greatest contribution was his conceptualization and characterization of circus movement reentry. His observations and ideas about the basis for cardiac reentrant activity underlie how we understand and manage a wide range of important clinical rhythm disturbances today. The notions he introduced regarding the influence of premature extrastimuli on reentry (termination, resetting and entrainment) are central to contemporary assessment of arrhythmia mechanisms in clinical electrophysiology laboratories and modern device therapy of cardiac tachyarrhythmias. Refinements of his model of reentry have led to sophisticated biophysical theories of the mechanisms underlying cardiac fibrillation. His seminal observations on the influence of electrolyte derangements and autonomic tone on the heart are relevant to our understanding of the physiology and pharmacology of arrhythmias caused by cardiac pathology. In this era of advanced technology, it is important to appreciate that ideas of lasting impact come from great minds and do not necessarily require great tools. PMID:26607760

  2. Sampling methods for exploring between-subject variability in cardiac electrophysiology experiments.

    Science.gov (United States)

    Drovandi, C C; Cusimano, N; Psaltis, S; Lawson, B A J; Pettitt, A N; Burrage, P; Burrage, K

    2016-08-01

    Between-subject and within-subject variability is ubiquitous in biology and physiology, and understanding and dealing with this is one of the biggest challenges in medicine. At the same time, it is difficult to investigate this variability by experiments alone. A recent modelling and simulation approach, known as population of models (POM), allows this exploration to take place by building a mathematical model consisting of multiple parameter sets calibrated against experimental data. However, finding such sets within a high-dimensional parameter space of complex electrophysiological models is computationally challenging. By placing the POM approach within a statistical framework, we develop a novel and efficient algorithm based on sequential Monte Carlo (SMC). We compare the SMC approach with Latin hypercube sampling (LHS), a method commonly adopted in the literature for obtaining the POM, in terms of efficiency and output variability in the presence of a drug block through an in-depth investigation via the Beeler-Reuter cardiac electrophysiological model. We show improved efficiency for SMC that produces similar responses to LHS when making out-of-sample predictions in the presence of a simulated drug block. Finally, we show the performance of our approach on a complex atrial electrophysiological model, namely the Courtemanche-Ramirez-Nattel model. PMID:27512137

  3. OptoDyCE: Automated system for high-throughput all-optical dynamic cardiac electrophysiology

    Science.gov (United States)

    Klimas, Aleksandra; Yu, Jinzhu; Ambrosi, Christina M.; Williams, John C.; Bien, Harold; Entcheva, Emilia

    2016-02-01

    In the last two decades, liability, adding to an already expensive and lengthy process. Recognition that proarrhythmic effects often result from drug action on multiple ion channels demonstrates a need for integrative and comprehensive measurements. Additionally, patient-specific therapies relying on emerging technologies employing stem-cell derived cardiomyocytes (e.g. induced pluripotent stem-cell-derived cardiomyocytes, iPSC-CMs) require better screening methods to become practical. However, a high-throughput, cost-effective approach for cellular cardiac electrophysiology has not been feasible. Optical techniques for manipulation and recording provide a contactless means of dynamic, high-throughput testing of cells and tissues. Here, we consider the requirements for all-optical electrophysiology for drug testing, and we implement and validate OptoDyCE, a fully automated system for all-optical cardiac electrophysiology. We demonstrate the high-throughput capabilities using multicellular samples in 96-well format by combining optogenetic actuation with simultaneous fast high-resolution optical sensing of voltage or intracellular calcium. The system can also be implemented using iPSC-CMs and other cell-types by delivery of optogenetic drivers, or through the modular use of dedicated light-sensitive somatic cells in conjunction with non-modified cells. OptoDyCE provides a truly modular and dynamic screening system, capable of fully-automated acquisition of high-content information integral for improved discovery and development of new drugs and biologics, as well as providing a means of better understanding of electrical disturbances in the heart.

  4. Using delay differential equations to induce alternans in a model of cardiac electrophysiology.

    Science.gov (United States)

    Eastman, Justin; Sass, Julian; Gomes, Johnny M; Dos Santos, Rodrigo Weber; Cherry, Elizabeth M

    2016-09-01

    Cardiac electrical alternans is a period-2 dynamical behavior with alternating long and short action potential durations (APD) that often precedes dangerous arrhythmias associated with cardiac arrest. Despite the importance of alternans, many current ordinary differential equations models of cardiac electrophysiology do not produce alternans, thereby limiting the use of these models for studying the mechanisms that underlie this condition. Because delay differential equations (DDEs) commonly induce complex dynamics in other biological systems, we investigate whether incorporating DDEs can lead to alternans development in cardiac models by studying the Fox et al. canine ventricular action potential model. After suppressing the alternans in the original model, we show that alternans can be obtained by introducing DDEs in the model gating variables, and we quantitatively compare the DDE-induced alternans with the alternans present in the original model. We analyze the behavior of the voltage, currents, and gating variables of the model to study the effects of the delays and to determine how alternans develops in that setting, and we discuss the mathematical and physiological implications of our findings. In future work, we aim to apply our approach to induce alternans in models that do not naturally exhibit such dynamics. PMID:27302910

  5. Program Code Generator for Cardiac Electrophysiology Simulation with Automatic PDE Boundary Condition Handling.

    Science.gov (United States)

    Punzalan, Florencio Rusty; Kunieda, Yoshitoshi; Amano, Akira

    2015-01-01

    Clinical and experimental studies involving human hearts can have certain limitations. Methods such as computer simulations can be an important alternative or supplemental tool. Physiological simulation at the tissue or organ level typically involves the handling of partial differential equations (PDEs). Boundary conditions and distributed parameters, such as those used in pharmacokinetics simulation, add to the complexity of the PDE solution. These factors can tailor PDE solutions and their corresponding program code to specific problems. Boundary condition and parameter changes in the customized code are usually prone to errors and time-consuming. We propose a general approach for handling PDEs and boundary conditions in computational models using a replacement scheme for discretization. This study is an extension of a program generator that we introduced in a previous publication. The program generator can generate code for multi-cell simulations of cardiac electrophysiology. Improvements to the system allow it to handle simultaneous equations in the biological function model as well as implicit PDE numerical schemes. The replacement scheme involves substituting all partial differential terms with numerical solution equations. Once the model and boundary equations are discretized with the numerical solution scheme, instances of the equations are generated to undergo dependency analysis. The result of the dependency analysis is then used to generate the program code. The resulting program code are in Java or C programming language. To validate the automatic handling of boundary conditions in the program code generator, we generated simulation code using the FHN, Luo-Rudy 1, and Hund-Rudy cell models and run cell-to-cell coupling and action potential propagation simulations. One of the simulations is based on a published experiment and simulation results are compared with the experimental data. We conclude that the proposed program code generator can be used to

  6. Modulatory role of verapamil treatment on the cardiac electrophysiological effects of cisapride.

    Science.gov (United States)

    Morissette, Pierre; Hreiche, Raymond; Turgeon, Jacques

    2006-12-01

    The role of transport proteins in the distribution of drugs in various tissues has obvious implications for drug effects. Recent reports indicate that such transporters are present not only in the liver, intestine, or blood-brain barrier but also in the heart. The objective of our study was to determine whether treatment of animals with verapamil, a well-known L-type calcium channel blocker with modulatory properties of membrane transporters, would alter distribution and cardiac electrophysiological effects of an I(Kr) blocker. Male guinea pigs (n = 72) were treated with either saline or verapamil at various doses (1.5 to 15 mg/kg) and for various durations (1 to 7 d). Animals were sacrificed 24 h after the last dose of verapamil (or saline), and their hearts were isolated and retroperfused with cisapride, a gastrokinetic drug with I(Kr) blockade properties. In hearts obtained from animals treated with vehicle, 50 nmol/L cisapride prolonged MAPD90 by 15 +/- 5 ms vs. 36 +/- 8 ms in hearts from animals treated with verapamil 15 mg.kg(-1).d(-1) for 5 d (p access to intracellular binding sites on I(Kr) channels. PMID:17487237

  7. Comparison of electrophysiological effects of calcium channel blockers on cardiac repolarization.

    Science.gov (United States)

    Lee, Hyang-Ae; Hyun, Sung-Ae; Park, Sung-Gurl; Kim, Ki-Suk; Kim, Sung Joon

    2016-01-01

    Dihydropyridine (DHP) calcium channel blockers (CCBs) have been widely used to treat of several cardiovascular diseases. An excessive shortening of action potential duration (APD) due to the reduction of Ca(2+) channel current (I Ca) might increase the risk of arrhythmia. In this study we investigated the electrophysiological effects of nicardipine (NIC), isradipine (ISR), and amlodipine (AML) on the cardiac APD in rabbit Purkinje fibers, voltage-gated K(+) channel currents (I Kr, I Ks) and voltage-gated Na(+) channel current (I Na). The concentration-dependent inhibition of Ca(2+) channel currents (I Ca) was examined in rat cardiomyocytes; these CCBs have similar potency on I Ca channel blocking with IC50 (the half-maximum inhibiting concentration) values of 0.142, 0.229, and 0.227 nM on NIC, ISR, and AML, respectively. However, ISR shortened both APD50 and APD90 already at 1 µM whereas NIC and AML shortened APD50 but not APD90 up to 30 µM. According to ion channel studies, NIC and AML concentration-dependently inhibited I Kr and I Ks while ISR had only partial inhibitory effects (NIC and AML could compensate for the AP shortening effects due to the block of I Ca.

  8. Stability analysis of the POD reduced order method for solving the bidomain model in cardiac electrophysiology.

    Science.gov (United States)

    Corrado, Cesare; Lassoued, Jamila; Mahjoub, Moncef; Zemzemi, Néjib

    2016-02-01

    In this paper we show the numerical stability of the Proper Orthogonal Decomposition (POD) reduced order method used in cardiac electrophysiology applications. The difficulty of proving the stability comes from the fact that we are interested in the bidomain model, which is a system of degenerate parabolic equations coupled to a system of ODEs representing the cell membrane electrical activity. The proof of the stability of this method is based on a priori estimates controlling the gap between the reduced order solution and the Galerkin finite element one. We present some numerical simulations confirming the theoretical results. We also combine the POD method with a time splitting scheme allowing a faster solving of the bidomain problem and show numerical results. Finally, we conduct numerical simulation in 2D illustrating the stability of the POD method in its sensitivity to the ionic model parameters. We also perform 3D simulation using a massively parallel code. We show the computational gain using the POD reduced order model. We also show that this method has a better scalability than the full finite element method. PMID:26723278

  9. Cardiac Electrophysiological Differences Between Kunming and C57BL6/J Mice

    Institute of Scientific and Technical Information of China (English)

    Teng Wang; Mu Qin; He Huang; Hong-liang Li; Cong-xin Huang

    2012-01-01

    Objective To investigate the alterations of cardiac electrophysiological properties and substantial mechanism and find the stable arrhythmia mouse model in Kunming (KM) and C57BL6/J (C57) mice.Methods Electrocardiogram recordings were used to analyze the QT interval in vivo,and monophasic action potential of right and left ventricular epicardium was recorded to elicit changes of action potential duration (APD) in conventional and programmed electrical stimtlation (PES).Transient outward potassium current (Iω) was recorded via whole-cell patch-clamp technique in single right and left epicardial myocytes.Results QT interval was prolonged in KM mice relative to C57 mice (62.51±4.47 ms vs.52.59±4.85 ms,P<0.05).The APD at 50% repolarization of the left ventricular epicardium (18.60±0.91 ms vs.12.90±0.35 ms),and APDs at 50% (17.31±6.05 ms vs.12.00±3.24 ms) and 70% repolarization (36.13±5.32 ms vs.21.95±8.06 ms) of the right ventricular epicardium in KM mice were significantly prolonged compared with C57 mice,respectively (all P<0.05).KM mice were more sensitive to PES-induced ventricular tachycardia (25%,3 of 12 hearts),and especially to Burst-induced ventricular tachycardia (50%,6 of 12 hearts) compared with C57 mice,which were 20% (2 of 10 hearts) and 30% (3 of 10 hearts) respectively.Ⅰto densities both in the left and right ventricular epicardial myocytes from KM mice were significantly decreased compared with C57 mice,respectively (all P<0.01 ).Conclusion Our data showed that KM mice with the prolonged QT interval and APD are vnlnerabilities to ventricular arrhythmia,which are attributed to lower Ⅰto densities in ventricular myocytes obtained from KM mice than that from C57 mice.

  10. Does electrophysiological testing have any role in risk stratification for sudden cardiac death?

    Institute of Scientific and Technical Information of China (English)

    Fei Lü; Wei Hua

    2010-01-01

    @@ Introduction Implantation of implantable cardioverter defibrillators (ICD) has widely been accepted for secondary prevention of sudden cardiac death (SCD) in cardiac arrest survivors.1 Currently there are increasing interests in primary prevention of SCD in selected high risk patients who have not experienced cardiac arrest.1

  11. In vivo effects of the IKr agonist NS3623 on cardiac electrophysiology of the guinea pig

    DEFF Research Database (Denmark)

    Hansen, Rie Schultz; Olesen, Søren-Peter; Rønn, Lars Christian B;

    2008-01-01

    are most often caused by antagonizing effects on the repolarizing cardiac current called IKr. In humans IKr is mediated by the human ether-a-go-go related gene (hERG) potassium channel. We recently presented NS3623, a compound that selectively activates this channel. The present study was dedicated......The long QT syndrome is characterized by a prolongation of the QT interval measured on the surface electrocardiogram. Prolonging the QT interval increases the risk of dangerous ventricular fibrillations, eventually leading to sudden cardiac death. Pharmacologically induced QT interval prolongations...

  12. Effect of regional differences in cardiac cellular electrophysiology on the stability of ventricular arrhythmias: a computational study

    Science.gov (United States)

    Clayton, Richard H.; Holden, Arun V.

    2003-01-01

    Re-entry is an important mechanism of cardiac arrhythmias. During re-entry a wave of electrical activation repeatedly propagates into recovered tissue, rotating around a rod-like filament. Breakdown of a single re-entrant wave into multiple waves is believed to underlie the transition from ventricular tachycardia to ventricular fibrillation. Several mechanisms of breakup have been identified including the effect of anisotropic conduction in the ventricular wall. Cells in the inner and outer layers of the ventricular wall have different action potential durations (APD), and support re-entrant waves with different periods. The aim of this study was to use a computational approach to study twisting and breakdown in a transmural re-entrant wave spanning these regions, and examine the relative role of this effect and anisotropic conduction. We used a simplified model of action potential conduction in the ventricular wall that we modified so that it supported stable re-entry in an anisotropic model with uniform APD. We first examined the effect of regional differences on breakdown in an isotropic model with transmural differences in APD, and found that twisting of the re-entrant filament resulted in buckling and breakdown during the second cycle of re-entry. We found that breakdown was amplified in the anisotropic model, resulting in complex activation in the region of longest APD. This study shows that regional differences in cardiac electrophysiology are a potentially important mechanism for destabilizing re-entry and may act synergistically with other mechanisms to mediate the transition from ventricular tachycardia to ventricular fibrillation.

  13. A numerical guide to the solution of the bidomain equations of cardiac electrophysiology

    KAUST Repository

    Pathmanathan, Pras

    2010-06-01

    Simulation of cardiac electrical activity using the bidomain equations can be a massively computationally demanding problem. This study provides a comprehensive guide to numerical bidomain modelling. Each component of bidomain simulations-discretisation, ODE-solution, linear system solution, and parallelisation-is discussed, and previously-used methods are reviewed, new methods are proposed, and issues which cause particular difficulty are highlighted. Particular attention is paid to the choice of stimulus currents, compatibility conditions for the equations, the solution of singular linear systems, and convergence of the numerical scheme. © 2010 Elsevier Ltd.

  14. Real-time x-ray fluoroscopy-based catheter detection and tracking for cardiac electrophysiology interventions

    Energy Technology Data Exchange (ETDEWEB)

    Ma Yingliang; Housden, R. James; Razavi, Reza; Rhode, Kawal S. [Division of Imaging Sciences and Biomedical Engineering, King' s College London, London SE1 7EH (United Kingdom); Gogin, Nicolas; Cathier, Pascal [Medisys Research Group, Philips Healthcare, Paris 92156 (France); Gijsbers, Geert [Interventional X-ray, Philips Healthcare, Best 5680 DA (Netherlands); Cooklin, Michael; O' Neill, Mark; Gill, Jaswinder; Rinaldi, C. Aldo [Department of Cardiology, Guys and St. Thomas' Hospitals NHS Foundation Trust, London SE1 7EH (United Kingdom)

    2013-07-15

    Purpose: X-ray fluoroscopically guided cardiac electrophysiology (EP) procedures are commonly carried out to treat patients with arrhythmias. X-ray images have poor soft tissue contrast and, for this reason, overlay of a three-dimensional (3D) roadmap derived from preprocedural volumetric images can be used to add anatomical information. It is useful to know the position of the catheter electrodes relative to the cardiac anatomy, for example, to record ablation therapy locations during atrial fibrillation therapy. Also, the electrode positions of the coronary sinus (CS) catheter or lasso catheter can be used for road map motion correction.Methods: In this paper, the authors present a novel unified computational framework for image-based catheter detection and tracking without any user interaction. The proposed framework includes fast blob detection, shape-constrained searching and model-based detection. In addition, catheter tracking methods were designed based on the customized catheter models input from the detection method. Three real-time detection and tracking methods are derived from the computational framework to detect or track the three most common types of catheters in EP procedures: the ablation catheter, the CS catheter, and the lasso catheter. Since the proposed methods use the same blob detection method to extract key information from x-ray images, the ablation, CS, and lasso catheters can be detected and tracked simultaneously in real-time.Results: The catheter detection methods were tested on 105 different clinical fluoroscopy sequences taken from 31 clinical procedures. Two-dimensional (2D) detection errors of 0.50 {+-} 0.29, 0.92 {+-} 0.61, and 0.63 {+-} 0.45 mm as well as success rates of 99.4%, 97.2%, and 88.9% were achieved for the CS catheter, ablation catheter, and lasso catheter, respectively. With the tracking method, accuracies were increased to 0.45 {+-} 0.28, 0.64 {+-} 0.37, and 0.53 {+-} 0.38 mm and success rates increased to 100%, 99

  15. Real-time x-ray fluoroscopy-based catheter detection and tracking for cardiac electrophysiology interventions

    International Nuclear Information System (INIS)

    Purpose: X-ray fluoroscopically guided cardiac electrophysiology (EP) procedures are commonly carried out to treat patients with arrhythmias. X-ray images have poor soft tissue contrast and, for this reason, overlay of a three-dimensional (3D) roadmap derived from preprocedural volumetric images can be used to add anatomical information. It is useful to know the position of the catheter electrodes relative to the cardiac anatomy, for example, to record ablation therapy locations during atrial fibrillation therapy. Also, the electrode positions of the coronary sinus (CS) catheter or lasso catheter can be used for road map motion correction.Methods: In this paper, the authors present a novel unified computational framework for image-based catheter detection and tracking without any user interaction. The proposed framework includes fast blob detection, shape-constrained searching and model-based detection. In addition, catheter tracking methods were designed based on the customized catheter models input from the detection method. Three real-time detection and tracking methods are derived from the computational framework to detect or track the three most common types of catheters in EP procedures: the ablation catheter, the CS catheter, and the lasso catheter. Since the proposed methods use the same blob detection method to extract key information from x-ray images, the ablation, CS, and lasso catheters can be detected and tracked simultaneously in real-time.Results: The catheter detection methods were tested on 105 different clinical fluoroscopy sequences taken from 31 clinical procedures. Two-dimensional (2D) detection errors of 0.50 ± 0.29, 0.92 ± 0.61, and 0.63 ± 0.45 mm as well as success rates of 99.4%, 97.2%, and 88.9% were achieved for the CS catheter, ablation catheter, and lasso catheter, respectively. With the tracking method, accuracies were increased to 0.45 ± 0.28, 0.64 ± 0.37, and 0.53 ± 0.38 mm and success rates increased to 100%, 99.2%, and 96

  16. Cardiac Electrophysiology Laboratories: A Potential Target for Antimicrobial Stewardship and Quality Improvement?

    Science.gov (United States)

    Branch-Elliman, Westyn; Stanislawski, Maggie; Strymish, Judith; Barón, Anna E; Gupta, Kalpana; Varosy, Paul D; Gold, Howard S; Ho, P Michael

    2016-09-01

    following cardiac device interventions may be a potential target for quality improvement programs and antimicrobial stewardship. Infect Control Hosp Epidemiol 2016;37:1005-1011. PMID:27322021

  17. On the Order of the Fractional Laplacian in Determining the Spatio-Temporal Evolution of a Space-Fractional Model of Cardiac Electrophysiology.

    Directory of Open Access Journals (Sweden)

    Nicole Cusimano

    Full Text Available Space-fractional operators have been used with success in a variety of practical applications to describe transport processes in media characterised by spatial connectivity properties and high structural heterogeneity altering the classical laws of diffusion. This study provides a systematic investigation of the spatio-temporal effects of a space-fractional model in cardiac electrophysiology. We consider a simplified model of electrical pulse propagation through cardiac tissue, namely the monodomain formulation of the Beeler-Reuter cell model on insulated tissue fibres, and obtain a space-fractional modification of the model by using the spectral definition of the one-dimensional continuous fractional Laplacian. The spectral decomposition of the fractional operator allows us to develop an efficient numerical method for the space-fractional problem. Particular attention is paid to the role played by the fractional operator in determining the solution behaviour and to the identification of crucial differences between the non-fractional and the fractional cases. We find a positive linear dependence of the depolarization peak height and a power law decay of notch and dome peak amplitudes for decreasing orders of the fractional operator. Furthermore, we establish a quadratic relationship in conduction velocity, and quantify the increasingly wider action potential foot and more pronounced dispersion of action potential duration, as the fractional order is decreased. A discussion of the physiological interpretation of the presented findings is made.

  18. On the Order of the Fractional Laplacian in Determining the Spatio-Temporal Evolution of a Space-Fractional Model of Cardiac Electrophysiology.

    Science.gov (United States)

    Cusimano, Nicole; Bueno-Orovio, Alfonso; Turner, Ian; Burrage, Kevin

    2015-01-01

    Space-fractional operators have been used with success in a variety of practical applications to describe transport processes in media characterised by spatial connectivity properties and high structural heterogeneity altering the classical laws of diffusion. This study provides a systematic investigation of the spatio-temporal effects of a space-fractional model in cardiac electrophysiology. We consider a simplified model of electrical pulse propagation through cardiac tissue, namely the monodomain formulation of the Beeler-Reuter cell model on insulated tissue fibres, and obtain a space-fractional modification of the model by using the spectral definition of the one-dimensional continuous fractional Laplacian. The spectral decomposition of the fractional operator allows us to develop an efficient numerical method for the space-fractional problem. Particular attention is paid to the role played by the fractional operator in determining the solution behaviour and to the identification of crucial differences between the non-fractional and the fractional cases. We find a positive linear dependence of the depolarization peak height and a power law decay of notch and dome peak amplitudes for decreasing orders of the fractional operator. Furthermore, we establish a quadratic relationship in conduction velocity, and quantify the increasingly wider action potential foot and more pronounced dispersion of action potential duration, as the fractional order is decreased. A discussion of the physiological interpretation of the presented findings is made. PMID:26629898

  19. Lessons from the heart: mirroring electrophysiological characteristics during cardiac development to in vitro differentiation of stem cell derived cardiomyocytes.

    Science.gov (United States)

    van den Heuvel, Nikki H L; van Veen, Toon A B; Lim, Bing; Jonsson, Malin K B

    2014-02-01

    The ability of human pluripotent stem cells (hPSCs) to differentiate into any cell type of the three germ layers makes them a very promising cell source for multiple purposes, including regenerative medicine, drug discovery, and as a model to study disease mechanisms and progression. One of the first specialized cell types to be generated from hPSC was cardiomyocytes (CM), and differentiation protocols have evolved over the years and now allow for robust and large-scale production of hPSC-CM. Still, scientists are struggling to achieve the same, mainly ventricular, phenotype of the hPSC-CM in vitro as their adult counterpart in vivo. In vitro generated cardiomyocytes are generally described as fetal-like rather than adult. In this review, we compare the in vivo development of cardiomyocytes to the in vitro differentiation of hPSC into CM with focus on electrophysiology, structure and contractility. Furthermore, known epigenetic changes underlying the differences between adult human CM and CM differentiated from pluripotent stem cells are described. This should provide the reader with an extensive overview of the current status of human stem cell-derived cardiomyocyte phenotype and function. Additionally, the reader will gain insight into the underlying signaling pathways and mechanisms responsible for cardiomyocyte development.

  20. Image-based view-angle independent cardiorespiratory motion gating and coronary sinus catheter tracking for x-ray-guided cardiac electrophysiology procedures

    International Nuclear Information System (INIS)

    Determination of the cardiorespiratory phase of the heart has numerous applications during cardiac imaging. In this article we propose a novel view-angle independent near-real time cardiorespiratory motion gating and coronary sinus (CS) catheter tracking technique for x-ray fluoroscopy images that are used to guide cardiac electrophysiology procedures. The method is based on learning CS catheter motion using principal component analysis and then applying the derived motion model to unseen images taken at arbitrary projections, using the epipolar constraint. This method is also able to track the CS catheter throughout the x-ray images in any arbitrary subsequent view. We also demonstrate the clinical application of our model on rotational angiography sequences. We validated our technique in normal and very low dose phantom and clinical datasets. For the normal dose clinical images we established average systole, end-expiration and end-inspiration gating success rates of 100%, 85.7%, and 92.3%, respectively. For very low dose applications, the technique was able to track the CS catheter with median errors not exceeding 1 mm for all tracked electrodes. Average gating success rates of 80.3%, 71.4%, and 69.2% were established for the application of the technique on clinical datasets, even with a dose reduction of more than 10 times. In rotational sequences at normal dose, CS tracking median errors were within 1.2 mm for all electrodes, and the gating success rate was 100%, for view angles from RAO 90° to LAO 90°. This view-angle independent technique can extract clinically useful cardiorespiratory motion information using x-ray doses significantly lower than those currently used in clinical practice. (paper)

  1. Cardiac electrophysiological characteristics after transplantation of differentiated bone marrow mesenchymal stem cells%诱导骨髓间充质干细胞分化移植后的心脏电生理特性

    Institute of Scientific and Technical Information of China (English)

    刘博武; 吕安林; 燕学波; 黄炜; 候婧; 李垚

    2011-01-01

    BACKGROUND: With the development of biotechnology, the electrophysiology of repairing heart tissues of myocardial infarction or myocardial hypertrophy by using bone marrow mesenchymal stem cell has become a hot spot. OBJECTIVE: To overview the research progress of cardiac electrophysiological characteristics after transplantation of induced differentiation of bone marrow mesenchymal stem cells into cardiomyocytes. METHODS: The databases of PubMed, Springer Link, Science Direct and CNKI were retrieved for papers published from January 2000 to October 2010 with the key words of "bone marrow mesenchymal stem cells, cardiac/heart, electrophysiology/electrophysiological characteristics". The relevant articles concerning cardiac electrophysiological characteristics of induce differentiation and transplantation of bone marrow stem cells were collected. RESULTS AND CONCLUSION: Totally 208 papers have been searched. Preliminary screening by reading abstracts to exclude 162 papers that study purpose do not coincident with this review either contents duplicated, and internalized 46 papers at last. Bone marrow mesenchymal stem cells after induced differentiation and transplantation could improve heart function of animal experimental model and myocardial infarction or myocardial hypertrophy patients. Although the cardiomyocyte-like cells from bone marrow mesenchymal stem cells could help to improve heart function, the cardiac electrophysiological characteristics may be influenced by them.%背景:随着生物技术的发展,使用骨髓间充质干细胞修复心肌梗死后或者心肌肥厚心肌组织的电生理学成为当今研究热点.目的:概述骨髓间充质干细胞向心肌细胞诱导分化移植后的电生理特征的研究进展.方法:应用计算机检索PubMed数据库,Springer Link数据库,Science Direct数据库,CNKI数据库2000-01/2010-10文献,检索词分别为"bone marrow mesenchymal stem cells,cardiac/heart,electrophysiology/ electrophysiological

  2. Robotics in invasive cardiac electrophysiology.

    Science.gov (United States)

    Shurrab, Mohammed; Schilling, Richard; Gang, Eli; Khan, Ejaz M; Crystal, Eugene

    2014-07-01

    Robotic systems allow for mapping and ablation of different arrhythmia substrates replacing hand maneuvering of intracardiac catheters with machine steering. Currently there are four commercially available robotic systems. Niobe magnetic navigation system (Stereotaxis Inc., St Louis, MO) and Sensei robotic navigation system (Hansen Medical Inc., Mountain View, CA) have an established platform with at least 10 years of clinical studies looking at their efficacy and safety. AMIGO Remote Catheter System (Catheter Robotics, Inc., Mount Olive, NJ) and Catheter Guidance Control and Imaging (Magnetecs, Inglewood, CA) are in the earlier phases of implementations with ongoing feasibility and some limited clinical studies. This review discusses the advantages and limitations related to each existing system and highlights the ideal futuristic robotic system that may include the most promising features of the current ones.

  3. Teaching Cardiac Electrophysiology Modeling to Undergraduate Students: Laboratory Exercises and GPU Programming for the Study of Arrhythmias and Spiral Wave Dynamics

    Science.gov (United States)

    Bartocci, Ezio; Singh, Rupinder; von Stein, Frederick B.; Amedome, Avessie; Caceres, Alan Joseph J.; Castillo, Juan; Closser, Evan; Deards, Gabriel; Goltsev, Andriy; Ines, Roumwelle Sta.; Isbilir, Cem; Marc, Joan K.; Moore, Diquan; Pardi, Dana; Sadhu, Sandeep; Sanchez, Samuel; Sharma, Pooja; Singh, Anoopa; Rogers, Joshua; Wolinetz, Aron; Grosso-Applewhite, Terri; Zhao, Kai; Filipski, Andrew B.; Gilmour, Robert F., Jr.; Grosu, Radu; Glimm, James; Smolka, Scott A.; Cherry, Elizabeth M.; Clarke, Edmund M.; Griffeth, Nancy; Fenton, Flavio H.

    2011-01-01

    As part of a 3-wk intersession workshop funded by a National Science Foundation Expeditions in Computing award, 15 undergraduate students from the City University of New York collaborated on a study aimed at characterizing the voltage dynamics and arrhythmogenic behavior of cardiac cells for a broad range of physiologically relevant conditions…

  4. Use of MRI: Multiple ways to enhance electrophysiology procedures

    NARCIS (Netherlands)

    Smink, J.; Weiss, S.; Wiethoff, A.; Gijsbers, G.

    2011-01-01

    This white paper summarizes the various ways in which MR may improve cardiac electrophysiology procedures of both types, catheter ablation and cardiac resynchronization therapy. The report gives an overview of how applications do or may benefit from pre-, post- and evenintra-operative MRI, focussin

  5. Past and future aspects of clinical electrophysiology.

    Science.gov (United States)

    Lüderitz, Berndt

    2008-01-01

    The diagnosis and treatment of clinical electrophysiology has a long and fascinating history. From the earliest time, no clinical symptom impressed the patient (and the physician) more than an irregular heart beat. Although ancient Chinese pulse theory laid the foundation for the study of arrhythmias and clinical electrophysiology in the 5th century BC, the most significant breakthrough in the identification and treatment of cardiac arrhythmias first occurred in this century. In the last decades, our knowledge of electrophysiology and pharmacology has increased exponentially. The enormous clinical significance of cardiac rhythm disturbances has favoured these advances. On the one hand, patients live longer and thus are more likely to experience arrhythmias. On the other hand, circulatory problems of the cardiac vessels have increased enormously, and this has been identified as the primary cause of cardiac rhythm disorders. Coronary heart disease has become not just the most significant disease of all, based on the statistics for cause of death. Arrhythmias are the main complication of ischemic heart disease, and they have been directly linked to the frequent arrhythmogenic sudden death syndrome, which is now presumed to be an avoidable "electrical accident" of the heart. A retrospective look--often charming in its own right--may not only make it easier to sort through the copious details of this field and so become oriented in this universe of important and less important facts; it may also assist the observer in a chronological vantage point of the subject. The study of clinical electrophysiology is no dry compendium of facts and figures, but rather a dynamic field of study evolving out of the competition between various ideas, intentions and theories. PMID:18651426

  6. Influence of Wenxin particle on cardiac electrophysiology in depressed rats after myocardial infarction%稳心颗粒对心肌梗死后抑郁大鼠心脏电生理的影响

    Institute of Scientific and Technical Information of China (English)

    梁锦军; 黄从新; 石少波; 谌晶晶; 王芳; 谌莹莹; 袁晓冉; 曲川; 黄鹤; 杨波

    2012-01-01

    目的:运用稳心颗粒干预心肌梗死后合并抑郁大鼠,探讨其对心梗后抑郁大鼠心脏电生理的影响.方法:选择SD大鼠50只,均分为正常组,心梗组,抑郁组,心梗后抑郁组(模型组)和稳心颗粒干预组(以2g/d的稳心颗粒给模型组大鼠灌胃28d).先后急性结扎左冠脉和予以慢性不可控的温和应激,制作心肌梗死后抑郁模型大鼠,予稳心颗粒干预,评价其对模型大鼠在体单向动作电位(MAP90)、左室有效不应期(ERP)和室颤阈值(VFT)等电生理学指标的影响.结果:(1)与正常组相比,模型组行为学评分有显著下降(P<0.05),经过4周稳心颗粒治疗后,其行为学评分显著上升(P<0.01);(2)与正常组相比,模型组MAPD90和ERP明显延长,VFT明显降低(P<0.05);稳心颗粒干预后,与模型组比较,稳心颗粒组MAPD90[(89.33±7.12)ms比(72.29±8.37)ms]、ERP[(84.00±6.57) ms比(68.00±7.43)ms]明显缩短,VFT[(7±3.11)V比(29±5.60) V]明显升高(P<0.05).结论:稳心颗粒能改善心肌梗死后抑郁大鼠心脏电重构,包括缩短单向动作电位和左室有效不应期,增加室颤阈值.%Objective:To investigate influence of Wenxin particle on cardiac electrophysiology in rats complicated with depression after myocardial infarction (MI).Methods:A total of 50 SD rats were randomly and equally divided into normal group,MI group,depression group,MI complicated depression group (modeI group) and Wenxin particle group (Wenxin particle were given to model rats by gavage,2 g/d,28d).Model (MI complicated with depresion) rats were made by acute ligation of left coronary artery and supply chronic unpredictable mild stress in order.The influences of wencin particle on cardiac electrophysiological indexes,such as monophasic action potential (MAP90),left ventricular effective refractory period (ERP) and ventricular fibrillation threshold (VFT) were evaluated in wencin particle group.Results:(1) Compared with normal group,there were

  7. Electrophysiological characteristics of the athlete's heart

    Directory of Open Access Journals (Sweden)

    Popović Dejana

    2007-01-01

    Full Text Available Introduction. The athletic heart syndrome is characterized by morphological, functional and electrophysiological alterations as an adaptive response to vigorous physical activity. Athletes heart is predominantly associated with a programmed, intensive training. But as there are different kinds of physical activities, the degree of these changes is highly variable. Electrophysiological characteristics of the athlete's heart. The response of the body to vigorous physical activity is a multiorgan system phenomenon. The integrated functioning of each of these organ systems is very important, but the cardiovascular system plays a critical role in mediating the activity. Because of that, most changes in the neurohumoral regulation pre- dominantly affect the cardiovascular system. These changes include: depression of sympathetic activity and stimulation of parasympathetic activity, so electrophysiological characteristics of the athlete's heart must differ from the sedentary. Although these facts, are well known, the athlete's heart is not a precisely defined concept. It is a gray zone between physiology and pathology. Conclusion. Considering the number of sudden cardiac deaths in athletes, it is needless to say how important it is to distinguish physiological changes of the heart due to physical activity, and pathological changes due to some cardiac diseases.

  8. Historical perspectives on interventional electrophysiology.

    Science.gov (United States)

    Lüderitz, Berndt

    2003-10-01

    The history of interventional electrophysiology is long and fascinating. In the beginning, there is not simply the anatomy and physiology of the heart, but also analysis of the pulse, which indicates the activity of the heart. The analysis of the (peripheral) pulse as a mechanical expression of heart activity goes back several millennia. In China, in 280 B.C., Wang Chu Ho wrote ten books about the pulse. The Greeks called the pulse "sphygmos", and the sphygmology thus deals with a theory of this natural occurrence. In Roman times, Galen interpreted the various types of pulse according to the widespread presumption of the time, that each organ in every disease has its own form of pulse. The basic tool for arrhythmia diagnosis became the electrocardiography introduced by Willem Einthoven who obtained the first human electrogram 1902 in Leiden, The Netherlands. The growing clinical importance of electrical cardiac stimulation has been recognized and renewed as Zoll (1911-1999) in 1952 reported a successful resuscitation in cardiac standstill by external stimulation. Meanwhile all over the world, millions of patients with cardiac arrhythmias have been treated with pacemakers in the last 45 years. The concept of a fully automatic implantable cardioverter-defibrillator system (ICD) for recognition and treatment of ventricular tachyarrhythmias was first suggested in 1970. The first implantation of the device in a human being was performed in February 1980. Further developments concern atrial and atrioventricular defibrillators, radiofrequency ablation, laser therapy and advanced antiarrhythmic surgery, new antiarrhythmic drugs and sophisticated devices for preventive pacing. The advances in the field of diagnostic and therapeutic application of pharmacologic and electrical tools as well as alternative methods will continue as rapidly as before in order to give us further significant aid in taking care of the patient.

  9. ICEPO: the ion channel electrophysiology ontology.

    Science.gov (United States)

    Hinard, V; Britan, A; Rougier, J S; Bairoch, A; Abriel, H; Gaudet, P

    2016-01-01

    Ion channels are transmembrane proteins that selectively allow ions to flow across the plasma membrane and play key roles in diverse biological processes. A multitude of diseases, called channelopathies, such as epilepsies, muscle paralysis, pain syndromes, cardiac arrhythmias or hypoglycemia are due to ion channel mutations. A wide corpus of literature is available on ion channels, covering both their functions and their roles in disease. The research community needs to access this data in a user-friendly, yet systematic manner. However, extraction and integration of this increasing amount of data have been proven to be difficult because of the lack of a standardized vocabulary that describes the properties of ion channels at the molecular level. To address this, we have developed Ion Channel ElectroPhysiology Ontology (ICEPO), an ontology that allows one to annotate the electrophysiological parameters of the voltage-gated class of ion channels. This ontology is based on a three-state model of ion channel gating describing the three conformations/states that an ion channel can adopt: closed, open and inactivated. This ontology supports the capture of voltage-gated ion channel electrophysiological data from the literature in a structured manner and thus enables other applications such as querying and reasoning tools. Here, we present ICEPO (ICEPO ftp site:ftp://ftp.nextprot.org/pub/current_release/controlled_vocabularies/), as well as examples of its use.

  10. Cardiac applications of optogenetics.

    Science.gov (United States)

    Ambrosi, Christina M; Klimas, Aleksandra; Yu, Jinzhu; Entcheva, Emilia

    2014-08-01

    In complex multicellular systems, such as the brain or the heart, the ability to selectively perturb and observe the response of individual components at the cellular level and with millisecond resolution in time, is essential for mechanistic understanding of function. Optogenetics uses genetic encoding of light sensitivity (by the expression of microbial opsins) to provide such capabilities for manipulation, recording, and control by light with cell specificity and high spatiotemporal resolution. As an optical approach, it is inherently scalable for remote and parallel interrogation of biological function at the tissue level; with implantable miniaturized devices, the technique is uniquely suitable for in vivo tracking of function, as illustrated by numerous applications in the brain. Its expansion into the cardiac area has been slow. Here, using examples from published research and original data, we focus on optogenetics applications to cardiac electrophysiology, specifically dealing with the ability to manipulate membrane voltage by light with implications for cardiac pacing, cardioversion, cell communication, and arrhythmia research, in general. We discuss gene and cell delivery methods of inscribing light sensitivity in cardiac tissue, functionality of the light-sensitive ion channels within different types of cardiac cells, utility in probing electrical coupling between different cell types, approaches and design solutions to all-optical electrophysiology by the combination of optogenetic sensors and actuators, and specific challenges in moving towards in vivo cardiac optogenetics.

  11. Hearing Aid Fitting & Electrophysiologic Procedure

    Directory of Open Access Journals (Sweden)

    Bahram Jalaei

    2001-05-01

    Full Text Available Rehabilitation of deaf individual is one of the important subjects that has attracted attention of many researchers during past centuries. Different opinions have been established in this direction. Electrophysiologic tests were established and developed parallel to developments in rehabilitation. Therefore, opinion of using electrophysiologic test for evaluation and fitting of hearing aid became gradually popular. Ultimately, the electrophysiologic tests are used in evaluation and fitting of hearing aid in two ways: 1-Direct way 2- Indirect way "nIn direct way aided ABR is obtained and special attention is paid to wave V. This technique has many difficulties. Inindirect way, electrophysiologic tests such, ECochG, OAE and ABR, AMLR, ALR and P300 and other objective tests are used, especially in infants and neonates for evaluating the state of hearing. Researches are continuing in this field. It is probable to have aided electrophysiologic responses with speech stimuli in near future.

  12. Diesel Exhaust Inhalation Increases Cardiac Output, Bradyarrhythmias, and Parasympathetic Tone in Aged Heart Failure-Prone Rats

    Science.gov (United States)

    Acute air pollutant inhalation is linked to adverse cardiac events and death, and hospitalizations for heart failure. Diesel exhaust (DE) is a major air pollutant suspected to exacerbate preexisting cardiac conditions, in part, through autonomic and electrophysiologic disturbance...

  13. Electrophysiology of living organs from first principles

    CERN Document Server

    Scharf, Günter

    2010-01-01

    Based on the derivation of the macroscopic Maxwell's equations by spatial averaging of the microscopic equations, we discuss the electrophysiology of living organs. Other methods of averaging (or homogenization) like the bidomain model are not compatible with Maxwell's theory. We also point out that modeling the active cells by source currents is not a suitable description of the situation from first principles. Instead, it turns out that the main source of the measured electrical potentials is the polarization charge density which exists at the membranes of the active cells and adds up to a macroscopic polarization. The latter is the source term in the Laplace equation, the solution of which gives the measured far-field potential. As a consequence it is the polarization or dipole density which is best suited for localization of cardiac arrhythmia.

  14. Lyme carditis. Electrophysiologic and histopathologic study

    International Nuclear Information System (INIS)

    To further define the nature of Lyme carditis, electrophysiologic study and endomyocardial biopsy were performed in a patient with Lyme disease, whose principal cardiac manifestation was high-degree atrioventricular block. Intracardiac recording demonstrated supra-Hisian block and complete absence of an escape mechanism. Gallium 67 scanning demonstrated myocardial uptake, and right ventricular endomyocardial biopsy revealed active lymphocytic myocarditis. A structure compatible with a spirochetal organism was demonstrated in one biopsy specimen. It is concluded that Lyme disease can produce active myocarditis, as suggested by gallium 67 imaging and confirmed by endomyocardial biopsy. Furthermore, the presence of high-grade atrioventricular block in this disease requires aggressive management with temporary pacemaker and corticosteroid therapy

  15. Electrophysiology in visually impaired children

    OpenAIRE

    Genderen, Maria Michielde van

    2006-01-01

    Inherited retinal disorders and posterior visual pathway abnormalities are important causes of visual impairment in children. Visual electrophysiology often is indispensable in diagnosing these conditions. This thesis shows the wide range of use of pediatric electro-ophthalmology, and demonstrates its value in establishing diagnoses and predicting the course of a disease, with consequences for the rehabilitation process. The electrophysiological results also contribute to the understanding of...

  16. Electrophysiological studies with prenalterol.

    Science.gov (United States)

    Weisswange, A; Csapo, G; Kalusche, D; Keck, M

    1982-01-01

    Electrophysiological studies with prenalterol in 19 patients (6 women, 13 men, 5 with sinus node disease, 4 with AV node disease, 7 with double node disease, 2 with conduction disturbance below His bundle, 1 normal) showed that sinus node function (heart rate, sinus node recovery time) is uniformly improved by this beta-stimulator. Also AV conduction is significantly and uniformly improved (shortening of AH interval and of the functional refractory period of AV conduction). There is no or little influence on intra-atrial conduction and on conduction below the His bundle. However, spontaneous depolarisation in His-Purkinje fibers--as tested in patients with complete AV block and ventricular demand pacemaker--is increased through beta-stimulation with prenalterol as reflected by shorter escape intervals and higher frequency escape rhythm. Prenalterol may be of clinical use in patients with cardiomyopathies who developed bradycardia under digitalisation or patients with severe bradyarrhythmia either with or without digitalis. It might also be useful in rare emergency situations, when complete pacemaker failure develops. PMID:6127883

  17. Electrophysiology and Biopotential Issues on Human Electrocardiogram-A Review

    Directory of Open Access Journals (Sweden)

    Mahmoud A.S. Ali

    2011-01-01

    Full Text Available Problem statement: The heart is the first organ and most importantly to form in the body, where is found the most powerful generator of electromagnetic energy in the human body. Electrophysiology is the best method used to diagnose human heart problem. Knowledge of the electrical potentials in human heart is a quantum leap in the science of the human heart. Recently, there has been a growing interest in studying the human ECG. However, is unfortunately a very complicated issue which requires a relatively good understanding of everything that has been said about the heart. Focus on the review of physical, electromagnetic basis of human heart's biopotentials and understanding the basic equations of cardiac electrophysiology that represents the basis to all clinicians whether in postnatal (pediatric or adult or prenatal (foetal Medicine. Approach: Mathematical method used for derivation of the essential equations of human heart electrical potentials, this equation will develop the principle sciences of human heart, the equation also outlier finding of the electromagnetic base of human electrophysiology. Results: Heart is important electrical generator in human body. The voltage and current which was generated in human heart represent the basis of heart biosciences. The electromagnetic energy of the heart not only envelops every cell of the human body, but also extends out in all directions in the space around human body. Conclusion: The proposed technique for electrophysiology and potentials on human ECG was useful and the results may contribute to the references for later studies.

  18. Effects of Different Implementation Methods of Semi-recumbent on Cardiac Electrophysiology in the Early Stage Patients of Acute Myocardial Infarction%不同操作方法半卧位对急性心肌梗死早期患者心电图的影响

    Institute of Scientific and Technical Information of China (English)

    刘丽英; 王建荣

    2014-01-01

    目的:观察不同操作方法半卧位对急性心肌梗死早期患者心电图的影响,探索适合此类患者的最佳半卧位操作方法.方法便利抽样选择入住我院CCU且发病12~24 h的急性心肌梗死患者28例,随机分为A组和B组,分别实施逐级抬高至半卧位和一步抬高至半卧位,观察并记录两组患者心率变异性(heart rate variability,HRV)指标:R-R间期标准差(stand-ard diviation of normal to normal intervals,SDNN)、相邻 RR 间期差值均方的平方根(root mean square of successive di-fleremes,RMssD);QT间期离散度指标:QT离散度(QT dispersion,QTd)及校正后的 QT离散度(heart-corrected QT disper-sion,QTcd).结果不同操作方法半卧位时,两组患者 SDNN、RMSSD、QTD、QTcd 的改变幅度,逐级半卧位组为(3.34±1.05)、(2.14±1.96)、(2.4±1.03)、(3.21±1.02)ms,小于直接半卧位组的(5.98±2.07)、(4.23±1.87)、(4.4±1.92)、(4.57±1.91)ms,差异均有统计学意义(均P<0.05).结论从心脏电生理角度而言,逐级半卧位实施法优于直接半卧位实施法,值得临床推广应用.%Objective To observe the different implementation methods semi-recumbent patients with acute myocardial infarction cardiac electrophysiology,exploring semi-recumbent implementation method suits these patients.Methods CCU and the incidence of 1 2-2 4 h 2 8 patients with acute myocardial infarc-tion were randomly divided into group A and group B,and implement step by step semi-recumbent and direct semi-recumbent respectively.The heart rate variability,standard deviation of normal to normal in-tervals,root mean square of successive differences,QT dispersion and heart-corrected QT dispersion were observed and recorded.Results The implementation of different methods of semi-recumbent posi-tion,the SDNN,RMSSD,QTD,QTcd of two groups of patients were changed,step by step semi-recum-bent group [(3.34±1.05)ms,(2.14±1.96)ms,(2.4±1.03)ms,(3.21±1

  19. Electrophysiological Evaluation in Lumbosacral Radiculopathy

    Directory of Open Access Journals (Sweden)

    Seyedeh Simindokht Hosseini

    2012-07-01

    Full Text Available Background: Prevalence of electrophysiological abnormalities in patients with lumbosacral radiculopathy was evaluated.Methods: A cross-sectional study was performed on 97 consecutive patients with the clinical diagnosis of lumbosacral radiculopathy. Complete neurological examinations and standard electrophysiological evaluation was performed on the patients.Results: Patients under study had the mean age of 46.4 ± 13.1 years (mean ± standard deviation. There were positive MRI findings in 64% of the patients. In 43% L5 root and in 40% S1 root was involved. Abnormal electrophysiological findings were recorded in 82% of the patients. In patients with pretibial muscle weakness, there were significant abnormalities recorded in compound motor action potential (CMAP amplitude of the common peroneal nerve. There was significantly increased frequency of electrophysiological abnormalities in the presence of chronic clinical symptoms (P = 0.001.Conclusion: The 82% positive findings in electrophysiological studies in the diagnosis of lumbosacral radiculopathy make it an efficacious tool in the evaluation of the patients suffering from lumbosacral radiculopathy.

  20. Functiogenesis of cardiac pacemaker activity.

    Science.gov (United States)

    Sakai, Tetsuro; Kamino, Kohtaro

    2016-07-01

    Throughout our investigations on the ontogenesis of the electrophysiological events in early embryonic chick hearts, using optical techniques to record membrane potential probed with voltage-sensitive dyes, we have introduced a novel concept of "functiogenesis" corresponding to "morphogenesis". This article gives an account of the framework of "functiogenesis", focusing on the cardiac pacemaker function and the functional organization of the pacemaking area. PMID:26719289

  1. Electrophysiologic and cellular characteristics of cardiomyocytes after X-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Frieß, Johannes L., E-mail: johannes.friess@h-ab.de [University for Applied Sciences Aschaffenburg, biomems lab, Würzburger Straße 45, 63743 Aschaffenburg (Germany); Heselich, Anja [Technische Universität Darmstadt, Developmental Biology and Neurogenetics, Schnittspahnstraße 13, 64287 Darmstadt (Germany); Ritter, Sylvia [Helmholtz Institute for Heavy Ion Research (GSI), Biophysics Department, Planckstraße 1, 64291 Darmstadt (Germany); Haber, Angelina; Kaiser, Nicole; Layer, Paul G. [Technische Universität Darmstadt, Developmental Biology and Neurogenetics, Schnittspahnstraße 13, 64287 Darmstadt (Germany); Thielemann, Christiane [University for Applied Sciences Aschaffenburg, biomems lab, Würzburger Straße 45, 63743 Aschaffenburg (Germany)

    2015-07-15

    Highlights: • Electrophysiologic and cellular effects of X-rays on primary cardiac cell cultures. • X-ray doses between 0.5 and 7 Gy. • Higher beat rate at reduced field action potential durations 7 days after exposure. • More increased cell cycle checkpoint arrest in G2/M than in G1/S phase. • Induced DSBs were mostly repaired within 24 h after irradiation. - Abstract: The aim of this study was to investigate possible effects of ionizing irradiation on the electrophysiological functionality of cardiac myocytes in vitro. Primary chicken cardiomyocytes with spontaneous beating activity were irradiated with X-rays (dose range of 0.5–7 Gy). Functional alterations of cardiac cell cultures were evaluated up to 7 days after irradiation using microelectrode arrays. As examined endpoints, cell proliferation, apoptosis, reactive oxygen species (ROS) and DNA damage were evaluated. The beat rate of the cardiac networks increased in a dose-dependent manner over one week. The duration of single action potentials was slightly shortened. Additionally, we observed lower numbers of mitotic and S-phase cells at certain time points after irradiation. Also, the number of cells with γH2AX foci increased as a function of the dose. No significant changes in the level of ROS were detected. Induction of apoptosis was generally negligibly low. This is the first report to directly show alterations in cardiac electrophysiology caused by ionizing radiation, which were detectable up to one week after irradiation.

  2. Electrophysiology in visually impaired children

    NARCIS (Netherlands)

    Genderen, Maria Michielde van

    2006-01-01

    Inherited retinal disorders and posterior visual pathway abnormalities are important causes of visual impairment in children. Visual electrophysiology often is indispensable in diagnosing these conditions. This thesis shows the wide range of use of pediatric electro-ophthalmology, and demonstrates i

  3. Tissue and Animal Models of Sudden Cardiac Death

    OpenAIRE

    Sallam, Karim; Li, Yingxin; Sager, Philip T.; Steven R. Houser; Wu, Joseph C.

    2015-01-01

    Sudden Cardiac Death (SCD) is a common cause of death in patients with structural heart disease, genetic mutations or acquired disorders affecting cardiac ion channels. A wide range of platforms exist to model and study disorders associated with SCD. Human clinical studies are cumbersome and are thwarted by the extent of investigation that can be performed on human subjects. Animal models are limited by their degree of homology to human cardiac electrophysiology including ion channel expressi...

  4. Hepato-cardiac disorders

    Institute of Scientific and Technical Information of China (English)

    Yasser; Mahrous; Fouad; Reem; Yehia

    2014-01-01

    Understanding the mutual relationship between the liver and the heart is important for both hepatologists and cardiologists. Hepato-cardiac diseases can be classified into heart diseases affecting the liver, liver diseases affecting the heart, and conditions affecting the heart and the liver at the same time. Differential diagnoses of liver injury are extremely important in a cardiologist’s clinical practice calling for collaboration between cardiologists and hepatologists due to the many other diseases that can affect the liver and mimic haemodynamic injury. Acute and chronic heart failure may lead to acute ischemic hepatitis or chronic congestive hepatopathy. Treatment in these cases should be directed to the primary heart disease. In patients with advanced liver disease, cirrhotic cardiomyopathy may develop including hemodynamic changes, diastolic and systolic dysfunctions, reduced cardiac performance and electrophysiological abnormalities. Cardiac evaluation is important for patients with liver diseases especially before and after liver transplantation. Liver transplantation may lead to the improvement of all cardiac changes and the reversal of cirrhotic cardiomyopathy. There are systemic diseases that may affect both the liver and the heart concomitantly including congenital, metabolic and inflammatory diseases as well as alcoholism. This review highlights these hepatocardiac diseases

  5. Atrial Electrophysiological Remodeling and Fibrillation in Heart Failure

    Science.gov (United States)

    Pandit, Sandeep V.; Workman, Antony J.

    2016-01-01

    Heart failure (HF) causes complex, chronic changes in atrial structure and function, which can cause substantial electrophysiological remodeling and predispose the individual to atrial fibrillation (AF). Pharmacological treatments for preventing AF in patients with HF are limited. Improved understanding of the atrial electrical and ionic/molecular mechanisms that promote AF in these patients could lead to the identification of novel therapeutic targets. Animal models of HF have identified numerous changes in atrial ion currents, intracellular calcium handling, action potential waveform and conduction, as well as expression and signaling of associated proteins. These studies have shown that the pattern of electrophysiological remodeling likely depends on the duration of HF, the underlying cardiac pathology, and the species studied. In atrial myocytes and tissues obtained from patients with HF or left ventricular systolic dysfunction, the data on changes in ion currents and action potentials are largely equivocal, probably owing mainly to difficulties in controlling for the confounding influences of multiple variables, such as patient’s age, sex, disease history, and drug treatments, as well as the technical challenges in obtaining such data. In this review, we provide a summary and comparison of the main animal and human electrophysiological studies to date, with the aim of highlighting the consistencies in some of the remodeling patterns, as well as identifying areas of contention and gaps in the knowledge, which warrant further investigation. PMID:27812293

  6. Electrophysiological study of intravenous pinaverium bromide in cardiology.

    Science.gov (United States)

    Guerot, C; Khemache, A; Sebbah, J; Noel, B

    1988-01-01

    Pinaverium bromide is a musculotropic spasmolytic agent which acts by inhibiting transmembrane calcium movements, an effect similar to that of verapamil. Because of this, an investigation was carried out to see if it had any electrophysiological effects in patients with various cardiac disorders. In an open study, 10 patients received 2 mg pinaverium bromide intravenously. In a double-blind study, 10 patients received 4 mg pinaverium bromide intravenously and 10 patients placebo. Patients included those with either normal or pathological basal conduction, such as bundle-branch block and 1st degree atrioventricular block. Measurements were made of electrophysiological parameters before and 10 minutes after injection. The results showed that neither of the two doses of pinaverium bromide had any effect on atrial excitability, sino-atrial conduction, node and trunk atrioventricular conduction or on intraventricular conduction. No significant difference was seen in comparison with placebo. Pinaverium bromide had no anti-arrhythmic properties in these studies. Local, cardiac and general clinical tolerability was good in all patients. PMID:3219882

  7. Parallel Optimization of 3D Cardiac Electrophysiological Model Using GPU

    Directory of Open Access Journals (Sweden)

    Yong Xia

    2015-01-01

    Full Text Available Large-scale 3D virtual heart model simulations are highly demanding in computational resources. This imposes a big challenge to the traditional computation resources based on CPU environment, which already cannot meet the requirement of the whole computation demands or are not easily available due to expensive costs. GPU as a parallel computing environment therefore provides an alternative to solve the large-scale computational problems of whole heart modeling. In this study, using a 3D sheep atrial model as a test bed, we developed a GPU-based simulation algorithm to simulate the conduction of electrical excitation waves in the 3D atria. In the GPU algorithm, a multicellular tissue model was split into two components: one is the single cell model (ordinary differential equation and the other is the diffusion term of the monodomain model (partial differential equation. Such a decoupling enabled realization of the GPU parallel algorithm. Furthermore, several optimization strategies were proposed based on the features of the virtual heart model, which enabled a 200-fold speedup as compared to a CPU implementation. In conclusion, an optimized GPU algorithm has been developed that provides an economic and powerful platform for 3D whole heart simulations.

  8. Olfaction in dragonflies: electrophysiological evidence.

    Science.gov (United States)

    Rebora, Manuela; Salerno, Gianandrea; Piersanti, Silvana; Dell'otto, Alessandro; Gaino, Elda

    2012-02-01

    The problem of olfaction in Paleoptera (Odonata, Ephemeroptera) cannot be considered fully elucidated until now. These insects have been traditionally considered anosmic, because their brain lacks glomerular antennal lobes, typically involved in Neoptera odor perception. In order to understand if the presumed coeloconic olfactory receptors described on the antennal flagellum of adult Odonata are really functioning, we performed an electrophysiological investigation with electroantennogram (EAG) and single cell recordings (SCR), using Libellula depressa L. (Odonata, Libellulidae) as a model species. Odors representing different chemical classes such as (Z)-3-hexenyl acetate (acetate ester), (E)-2-hexenal, octanal (aldehydes), (Z)-3-hexen-1-ol (alcohol), propionic acid, butyric acid (carboxylic acids), and 1,4-diaminobutane (amine) were tested. Most of the tested chemicals elicited depolarizing EAG responses in both male and female antennae; SCR show unambiguously for the first time the presence of olfactory neurons in the antennae of L. depressa and strongly support the olfactory function of the coeloconic sensilla located on the antennal flagellum of this species. Electrophysiological activity may not necessarily indicate behavioral activity, and the biological role of olfactory responses in Odonata must be determined in behavioral bioassays. This study represents a starting point for further behavioral, electrophysiological, neuroanatomical and molecular investigation on Odonata olfaction, a research field particularly interesting owing to the basal position of Paleoptera, also for tracing evolutionary trends in insect olfaction. PMID:22154954

  9. Gender differences in cardiac hypertrophic remodeling.

    Science.gov (United States)

    Patrizio, Mario; Marano, Giuseppe

    2016-01-01

    Cardiac remodeling is a complex process that occurs in response to different types of cardiac injury such as ischemia and hypertension, and that involves cardiomyocytes, fibroblasts, vascular smooth muscle cells, vascular endothelial cells, and inflammatory cells. The end result is cardiomyocyte hypertrophy, fibrosis, inflammation, vascular, and electrophysiological remodeling. This paper reviews a large number of studies on the influence of gender on pathological cardiac remodeling and shows how sex differences result in different clinical outcomes and therapeutic responses, with males which generally develop greater cardiac remodeling responses than females. Although estrogens appear to have an important role in attenuating adverse cardiac remodeling, the mechanisms through which gender modulates myocardial remodeling remain to be identified. PMID:27364397

  10. Toward microendoscopy-inspired cardiac optogenetics in vivo: technical overview and perspective

    Science.gov (United States)

    Klimas, Aleksandra; Entcheva, Emilia

    2014-08-01

    The ability to perform precise, spatially localized actuation and measurements of electrical activity in the heart is crucial in understanding cardiac electrophysiology and devising new therapeutic solutions for control of cardiac arrhythmias. Current cardiac imaging techniques (i.e. optical mapping) employ voltage- or calcium-sensitive fluorescent dyes to visualize the electrical signal propagation through cardiac syncytium in vitro or in situ with very high-spatiotemporal resolution. The extension of optogenetics into the cardiac field, where cardiac tissue is genetically altered to express light-sensitive ion channels allowing electrical activity to be elicited or suppressed in a precise cell-specific way, has opened the possibility for all-optical interrogation of cardiac electrophysiology. In vivo application of cardiac optogenetics faces multiple challenges and necessitates suitable optical systems employing fiber optics to actuate and sense electrical signals. In this technical perspective, we present a compendium of clinically relevant access routes to different parts of the cardiac electrical conduction system based on currently employed catheter imaging systems and determine the quantitative size constraints for endoscopic cardiac optogenetics. We discuss the relevant technical advancements in microendoscopy, cardiac imaging, and optogenetics and outline the strategies for combining them to create a portable, miniaturized fiber-based system for all-optical interrogation of cardiac electrophysiology in vivo.

  11. Cardiac arrest

    Science.gov (United States)

    ... Article.jsp. Accessed June 16, 2014. Myerburg RJ, Castellanos A. Approach to cardiac arrest and life-threatening ... PA: Elsevier Saunders; 2011:chap 63. Myerburg RJ, Castellanos A. Cardiac arrest and audden aardiac death. In: ...

  12. Introduction to noninvasive cardiac mapping.

    Science.gov (United States)

    Bear, Laura; Cuculich, Phillip S; Bernus, Olivier; Efimov, Igor; Dubois, Rémi

    2015-03-01

    From the dawn of the twentieth century, the electrocardiogram (ECG) has revolutionized the way clinical cardiology has been practiced, and it has become the cornerstone of modern medicine today. Driven by clinical and research needs for a more precise understanding of cardiac electrophysiology beyond traditional ECG, inverse solution electrocardiography has been developed, tested, and validated. This article outlines the important progress from ECG development, through more extensive measurement of body surface potentials, and the fundamental leap to solving the inverse problem of electrocardiography, with a focus on mathematical methods and experimental validation. PMID:25784020

  13. 10.2.Cardiac arrhythmias

    Institute of Scientific and Technical Information of China (English)

    1993-01-01

    930257 Electrophysiologic study of reperfu-sion arrhythmias.YIN Hong (尹红),et al.Af-fil Hosp,Shandong Med Univ,Jinan.Chin CirJ 1993;8(1):37—39.Twenty dogs of experimental ischemic reper-fusion were studied with a three-dimensionalmapping system of cardiac electric activity andmultiple—level myocardial recordings by bipolarplunge—needle electrodes.27% of the nonsus-tained ventricular tachycardia (NSVT) of intra-mural reentry occurred in the ischemic subendo-

  14. Electrophysiological effects of hydrogen sulfide on human atrial fibers

    Institute of Scientific and Technical Information of China (English)

    XU Meng; WU Yu-ming; LI Qian; LIU Su; HE Rui-rong

    2011-01-01

    Background It has been reported that endogenous or exogenous hydrogen sulfide (H2S) exerts physiological effects in the vertebrate cardiovascular system.We have also demonstrated that H2S acts as an important regulator of electrophysiological properties in guinea pig papillary muscles and on pacemaker cells in sinoatrial nodes of rabbits.This study was to observe the electrophysiological effects of H2S on human atrial fibers.Methods Human atrial samples were collected during cardiac surgery.Parameters of action potential in human atrial specialized fibers were recorded using a standard intracellular microelectrode technique.Results NaHS (H2S donor) (50,100 and 200 μmol/L) decreased the amplitude of action potential (APA),maximal rate of depolarization (Vmax),velocity of diastolic (phase 4) depolarization (VDD) and rate of pacemaker firing (RPF),and shortened the duration of 90% repolarization (APD90) in a concentration-dependent manner.ATP-sensitive K+ (KATP)channel blocker glibenclamide (Gli,20 μmol/L) partially blocked the effects of NaHS (100 μmol/L) on human atrial fiber cells.The L-type Ca2+ channel agonist Bay K8644 (0.5 μmol/L) also partially blocked the effects of NaHS (100 μmol/L).An inhibitor of cystathionine y-lyase (CSE),DL-propargylglycine (PPG,200 μmol/L),increased APA,Vmax,VDD and RPF,and prolonged APD90.Conclusions H2S exerts a negative chronotropic action and accelerates the repolarization of human atrial specialized fibers,possibly as a result of increases in potassium efflux through the opening of KATP channels and a concomitant decrease in calcium influx.Endogenous H2S may be generated by CSE and act as an important regulator of electrophysiological properties in human atrial fibers.

  15. Computational models of atrial cellular electrophysiology and calcium handling, and their role in atrial fibrillation.

    Science.gov (United States)

    Heijman, Jordi; Erfanian Abdoust, Pegah; Voigt, Niels; Nattel, Stanley; Dobrev, Dobromir

    2016-02-01

    The complexity of the heart makes an intuitive understanding of the relative contribution of ion channels, transporters and signalling pathways to cardiac electrophysiology challenging. Computational modelling of cardiac cellular electrophysiology has proven useful to integrate experimental findings, extrapolate results obtained in expression systems or animal models to other systems, test quantitatively ideas based on experimental data and provide novel hypotheses that are experimentally testable. While the bulk of computational modelling has traditionally been directed towards ventricular bioelectricity, increasing recognition of the clinical importance of atrial arrhythmias, particularly atrial fibrillation, has led to widespread efforts to apply computational approaches to understanding atrial electrical function. The increasing availability of detailed, atrial-specific experimental data has stimulated the development of novel computational models of atrial-cellular electrophysiology and Ca(2+) handling. To date, more than 300 studies have employed mathematical simulations to enhance our understanding of atrial electrophysiology, arrhythmogenesis and therapeutic responses. Future modelling studies are likely to move beyond current whole-cell models by incorporating new data on subcellular architecture, macromolecular protein complexes, and localized ion-channel regulation by signalling pathways. At the same time, more integrative multicellular models that take into account regional electrophysiological and Ca(2+) handling properties, mechano-electrical feedback and/or autonomic regulation will be needed to investigate the mechanisms governing atrial arrhythmias. A combined experimental and computational approach is expected to provide the more comprehensive understanding of atrial arrhythmogenesis that is required to develop improved diagnostic and therapeutic options. Here, we review this rapidly expanding area, with a particular focus on Ca(2+) handling, and

  16. 高发心脏性猝死的3型长QT综合征一家系报道%High incidence of sudden cardiac death in one family with type-3 long QT syndrome: molecular genetics and electrophysiology mechanism analysis

    Institute of Scientific and Technical Information of China (English)

    周慧; Li Zhang; Ali Raza Ghani; 朱文根; 周琼琼; 申阳; 谢金燕; 曹青; 万蓉

    2015-01-01

    Objectives We identified the long QT syndrome (LQTS) patients,and detected the potential risk of LQTS in family members by using genetic testing and electrophysiological analysis,which helped provide clinical evaluation and appropriate treatment.Methods Detailed clinical characteristics and familiar history were obtained from the whole family members of an idiopathic pediatric LQTS patient.Two hundred healthy subjects with the same ethnic background were recruited as controls.The entire coding sequences of three candidate genes including KCNQ1,KCNH2 and SCN5A were screened for mutations in the proband.The function of the mutation was then explored by whole-cell patch clamp techniques,and the genetic testing and risk assessment of the family members were performed.Results The proband was clinically preliminary diagnosed as LQTS by 12-lead electrocardiogram.On the third day of metoprolol intake (25 mg,bid),she died suddenly at lunch.One heterozygous missense mutation (SCN5A-V411 M) was identified in this proband,but the mutation was absent in 200 healthy subjects.The electrophysiological analysis indicated that SCN5A-V411M significantly increased the peak current density ((230.8 ± 27.6)pA/ pF vs.(101.2 ± 10.9)pA/pF,n =10,P <0.01) and the late sodium current ((156.6 ± 13.6) pA/pF vs.(95.9 ± 7.9) pA/pF,n =12,P < 0.01) of sodium channel compared to wide type.The enhanced sodium channel activation with a negative shift in the peak Ⅰ-V relationship was significantly higher by-50 mV than wide type (85.0% ± 7.4% vs.41.5% ± 2.6%,P < 0.01),while the steady-state inactivation curves remained unchanged.Additionally,mother and grandmother of the proband were the silent mutation carriers with no symptoms,who needed the appropriate clinical assessment and follow-up.The proband's twin sister and aunt died of sudden infant death syndrome.Conclusions We firstly reported a heterozygote missense mutation (SCN5A-V411M) in this Chinese family.V411M induced "gain of

  17. Working memory of emotional stimuli: Electrophysiological characterization.

    Science.gov (United States)

    Kessel, Dominique; García-Rubio, María J; González, E Kirstin; Tapia, Manuel; López-Martín, Sara; Román, Francisco J; Capilla, Almudena; Martínez, Kenia; Colom, Roberto; Carretié, Luis

    2016-09-01

    Memorizing emotional stimuli in a preferential way seems to be one of the adaptive strategies brought on by evolution for supporting survival. However, there is a lack of electrophysiological evidence on this bias in working memory. The present study analyzed the influence of emotion on the updating component of working memory. Behavioral and electrophysiological indices were measured from a 3-back task using negative, neutral, and positive faces. Electrophysiological data evidenced an emotional influence on the working memory sensitive P3 component, which presented larger amplitudes for negative matching faces compared to neutral ones. This effect originated in the superior parietal cortex, previously reported to be involved in N-back tasks. Additionally, P3 results showed a correlation with reaction times, where higher amplitudes were associated with faster responses for negative matching faces. These findings indicate that electrophysiological measures seem to be very suitable indices of the emotional influence on working memory. PMID:27402441

  18. Working memory of emotional stimuli: Electrophysiological characterization.

    Science.gov (United States)

    Kessel, Dominique; García-Rubio, María J; González, E Kirstin; Tapia, Manuel; López-Martín, Sara; Román, Francisco J; Capilla, Almudena; Martínez, Kenia; Colom, Roberto; Carretié, Luis

    2016-09-01

    Memorizing emotional stimuli in a preferential way seems to be one of the adaptive strategies brought on by evolution for supporting survival. However, there is a lack of electrophysiological evidence on this bias in working memory. The present study analyzed the influence of emotion on the updating component of working memory. Behavioral and electrophysiological indices were measured from a 3-back task using negative, neutral, and positive faces. Electrophysiological data evidenced an emotional influence on the working memory sensitive P3 component, which presented larger amplitudes for negative matching faces compared to neutral ones. This effect originated in the superior parietal cortex, previously reported to be involved in N-back tasks. Additionally, P3 results showed a correlation with reaction times, where higher amplitudes were associated with faster responses for negative matching faces. These findings indicate that electrophysiological measures seem to be very suitable indices of the emotional influence on working memory.

  19. Mesenchymal stem cells improve cardiac conduction by upregulation of connexin 43 through paracrine signaling

    OpenAIRE

    Mureli, Shwetha; Gans, Christopher P.; Bare, Dan J; Geenen, David L.; Kumar, Nalin M.; Banach, Kathrin

    2012-01-01

    Mesenchymal stem cells (MSCs) were shown to improve cell survival and alleviate cardiac arrhythmias when transplanted into cardiac tissue; however, little is known about the mechanism by which MSCs modify the electrophysiological properties of cardiac tissue. We aimed to distinguish the influence of cell-cell coupling between myocytes and MSCs from that of MSC-derived paracrine factors on the spontaneous activity and conduction velocity (θ) of multicellular cardiomyocyte preparations. HL-1 ce...

  20. Electrophysiological Recording From Drosophila Labellar Taste Sensilla

    OpenAIRE

    Delventhal, Rebecca; Kiely, Aidan; Carlson, John R.

    2014-01-01

    The peripheral taste response of insects can be powerfully investigated with electrophysiological techniques. The method described here allows the researcher to measure gustatory responses directly and quantitatively, reflecting the sensory input that the insect nervous system receives from taste stimuli in its environment. This protocol outlines all key steps in performing this technique. The critical steps in assembling an electrophysiology rig, such as selection of necessary equipment and ...

  1. Cardiac Malpositions

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Shi Joon; Im, Chung Gie; Yeon, Kyung Mo; Hasn, Man Chung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1979-06-15

    Cardiac Malposition refers to any position of the heart other than a left-sided heart in a situs solitus individual. Associated cardiac malformations are so complex that even angiocardiographic and autopsy studies may not afford an accurate information. Although the terms and classifications used to describe the internal cardiac anatomy and their arterial connections in cardiac malpositions differ and tend to be confusing, common agreement exists on the need for a segmental approach to diagnosis. Authors present 18 cases of cardiac malpositions in which cardiac catheterization and angiocardiography were done at the Department of Radiology, Seoul National University Hospital between 1971 and 1979. Authors analyzed the clinical, radiographic, operative and autopsy findings with the emphasis on the angiocardiographic findings. The results are as follows: 1. Among 18 cases with cardiac malpositions, 6 cases had dextrocardia with situs inversus, 9 cases had dextrocardia with situs solitus and 3 cases had levocardia with situs inversus. 2. There was no genuine exception to visceroatrial concordance rule. 3. Associated cardiac malpositions were variable and complex with a tendency of high association of transposition and double outlet varieties with dextrocardia in situs solitus and levocardia in situs inversus. Only one in 6 cases of dextrocardia with situs inversus had pure transposition. 4. In two cases associated pulmonary atresia was found at surgery which was not predicted by angiocardiography. 5. Because many of the associated complex lesions can be corrected surgically provided the diagnosis is accurate, the selective biplane angiocardiography with or without cineradiography is essential.

  2. Improving cardiomyocyte model fidelity and utility via dynamic electrophysiology protocols and optimization algorithms.

    Science.gov (United States)

    Krogh-Madsen, Trine; Sobie, Eric A; Christini, David J

    2016-05-01

    Mathematical models of cardiac electrophysiology are instrumental in determining mechanisms of cardiac arrhythmias. However, the foundation of a realistic multiscale heart model is only as strong as the underlying cell model. While there have been myriad advances in the improvement of cellular-level models, the identification of model parameters, such as ion channel conductances and rate constants, remains a challenging problem. The primary limitations to this process include: (1) such parameters are usually estimated from data recorded using standard electrophysiology voltage-clamp protocols that have not been developed with model building in mind, and (2) model parameters are typically tuned manually to subjectively match a desired output. Over the last decade, methods aimed at overcoming these disadvantages have emerged. These approaches include the use of optimization or fitting tools for parameter estimation and incorporating more extensive data for output matching. Here, we review recent advances in parameter estimation for cardiomyocyte models, focusing on the use of more complex electrophysiology protocols and global search heuristics. We also discuss future applications of such parameter identification, including development of cell-specific and patient-specific mathematical models to investigate arrhythmia mechanisms and predict therapy strategies. PMID:26661516

  3. Generation of electrophysiologically functional cardiomyocytes from mouse induced pluripotent stem cells

    Directory of Open Access Journals (Sweden)

    Hongran Wang

    2016-03-01

    Full Text Available Induced pluripotent stem (iPS cells can efficiently differentiate into the three germ layers similar to those formed by differentiated embryonic stem (ES cells. This provides a new source of cells in which to establish preclinical allogeneic transplantation models. Our iPS cells were generated from mouse embryonic fibroblasts (MEFs transfected with the Yamanaka factors, the four transcription factors (Oct4, Sox2, Klf4 and c-Myc, without antibiotic selection or MEF feeders. After the formation of embryoid bodies (EBs, iPS cells spontaneously differentiated into Flk1-positive cardiac progenitors and cardiomyocytes expressing cardiac-specific markers such as alpha sarcomeric actinin (α-actinin, cardiac alpha myosin heavy chain (α-MHC, cardiac troponin T (cTnT, and connexin 43 (CX43, as well as cardiac transcription factors Nk2 homebox 5 (Nkx2.5 and gata binding protein 4 (gata4. The electrophysiological activity of iPS cell-derived cardiomyocytes (iPS-CMs was detected in beating cell clusters with optical mapping and RH237 a voltage-sensitive dye, and in single contracting cells with patch-clamp technology. Incompletely differentiated iPS cells formed teratomas when transplanted into a severe combined immunodeficiency (SCID mouse model of myocardial infarction. Our results show that somatic cells can be reprogrammed into pluripotent stem cells, which in turn spontaneously differentiate into electrophysiologically functional mature cardiomyocytes expressing cardiac-specific makers, and that these cells can potentially be used to repair myocardial infarction (MI in the future.

  4. Particles Alter Diesel Exhaust Gases-Induced Hypotension, Cardiac Arrhythmia,Conduction Disturbance, and Autonomic Imbalance in Heart Failure-Prone Rats

    Science.gov (United States)

    Epidemiologic studies indicate that acute exposures to vehicular traffic and particulate matter (PM) air pollution are key causes of fatal cardiac arrhythmia, especially in those with preexisting cardiovascular disease. Researchers point to electrophysiologic dysfunction and auto...

  5. Ventricular Torsion and Cardiac Suction Effect. The Electrophysiological Analysis of the Cardiac Band Muscle

    OpenAIRE

    The Editors

    2014-01-01

    Adult and aged population provide the vast majority of potential diseased people in Europe, the Americas and Japan. Their needs of mobility support and rehabilitation may be categorized as minimal (young light subjects during and after light traumatic events), medium (old subjects with impairments in the normal life activity and sarcopenia), severe (advanced sarcopenia in older old subjects, oncology, neuromuscular and skeletal disorders, subjects weaning from long hospitalization for heavy s...

  6. Evolving anatomic and electrophysiologic considerations associated with Fontan conversion.

    Science.gov (United States)

    Mavroudis, Constantine; Backer, Carl Lewis; Deal, Barbara J; Stewart, Robert D; Franklin, Wayne H; Tsao, Sabrina; Ward, Kendra

    2007-01-01

    The principles of Fontan conversion with arrhythmia surgery are to restore the cardiac anatomy by converting the original atriopulmonary connection to a total cavopulmonary artery extracardiac connection and treat the underlying atrial arrhythmias. Successful outcomes of this procedure are dependent on a thorough understanding of several factors: the patient's fundamental diagnosis of single-ventricle anatomy, the resultant cardiac configuration from the original atriopulmonary Fontan connection, right atrial dilatation that leads to atrial flutter or fibrillation, and associated congenital cardiac anomalies. The purpose of this article is to present some of the more challenging anatomic and electrophysiologic problems we have encountered with Fontan conversion and arrhythmia surgery and the innovative solutions we have used to treat them. The cases reviewed herein include: takedown of a Bjork-Fontan modification, right ventricular hypertension and tricuspid regurgitation after atriopulmonary Fontan for pulmonary atresia and intact ventricular septum, takedown of atrioventricular valve isolation patch for right-sided maze procedure, resultant hemodynamic considerations leading to intraoperative pulmonary vein stenosis after Fontan conversion, unwanted inferior vena cava retraction during the extracardiac connection, right atrial cannulation in the presence of a right atrial clot, distended left superior vena cava causing left pulmonary vein stenosis, dropped atrial septum, and the modified right-sided maze procedure for various single-ventricle pathology. Since 1994 we have performed Fontan conversion with arrhythmia surgery on 109 patients with a 0.9% mortality rate. We attribute our program's success in no small measure to the strong collaborative efforts of the cardiothoracic surgery and cardiology teams.

  7. The comparison of cardiac stem cells and mesenchymal stem cells transplantation in improving the ventricular fibrillation threshold and electrophysiological stability in rats with myocardial infarction%心肌干细胞和骨髓间充质干细胞改进心肌梗死大鼠室颤阈值和心电生理稳定性的对比研究

    Institute of Scientific and Technical Information of China (English)

    陈立朋; 郭天柱; 郑韶欣; 侯婧瑛; 周长青; 龙会宝; 钟婷婷; 王彤

    2015-01-01

    目的 比较心肌干细胞(cardiac stem cells,CSCs)和骨髓间充质干细胞(mesenchymal stem cells,MSCs)对心肌梗死(myocardial infarction,MI)大鼠室颤阈值和心电生理学稳定性的影响.方法 通过开胸结扎30只SD大鼠左前降支冠状动脉建立心肌梗死模型,2周后随机(随机数字法)分为CSCs组、MSCs组及PBS组,每组各10只,分别于局部梗死心肌内注射PKH26荧光标记的CSCs、MSCs或等量PBS.治疗6周后,再次开胸检测梗死边缘区的心电生理特性和室颤阈值.实验结束后,摘取心脏行病理切片,检查PKH26标记的CSCs、MSCs是否在梗死边缘区内生存并表达连接蛋白43.结果 CSCs组移植6周后其梗死边缘区单极电图激动恢复时间、纠正的激动恢复时间与MSCs组及对照组比较,差异无统计学意义(P>0.05);CSCs组梗死边缘区单极电图纠正的激动恢复时间离散度、电刺激所激发的恶性心律失常及室颤阈值与MSCs组及对照组比较,差异具有统计学意义(P<0.05);在上述指标方面,MSCs组和PBS组比较,均差异无统计学意义(P>0.05).PKH26标记的CSCs在梗死边缘区内被发现并表达连接蛋白43,而PKH26标记的存在于梗死边缘区的MSCs则很少表达连接蛋白43.结论 CSCs移植和MSCs移植治疗心肌梗死是比较安全有效的,无明显致心律失常性.CSCs移植后6周其心电生理学稳定性改善和室颤阈值提高的效应较MSCs优越,CSCs是治疗心血管疾病较为理想的种子细胞.%Objective To compare the effects of cardiac stem cells (CSCs) versus mesenchymal stem ceils (MSCs) transplantation on the electrophysiological stability and ventricular fibrillation threshold (VFT) in rats with myocardial infarction (MI).Methods In 30 Sprague-Dawley rats,the left anterior descending coronary artery ligation was carried out to induce MI.Two weeks later,animals were randomly (random number) divided into three groups:CSCs group (n =10),MSCs group (n =10) and

  8. Cardiac rehabilitation

    Science.gov (United States)

    ... attack or other heart problem. You might consider cardiac rehab if you have had: Heart attack Coronary heart disease (CHD) Heart failure Angina (chest pain) Heart or heart valve surgery Heart transplant Procedures such as angioplasty and stenting In some ...

  9. Electrophysiological mechanisms of sophocarpine as a potential antiarrhythmic agent

    Institute of Scientific and Technical Information of China (English)

    Zhi-fang YANG; Ci-zhen LI; Wei WANG; Ying-min CHEN; Ying ZHANG; Yuan-mou LIU; Hong-wei WANG

    2011-01-01

    Aim: To examine the electrophysiological effects of sophocarpine on action potentials (AP) and ionic currents of cardiac myocytes and to compare some of these effects with those of amiodarone.Methods: Langendorff perfusion set-up was used in isolated guinea pig heart, and responses to sophocarpine were monitored using electrocardiograph. Conventional microelectrode, voltage clamp technique and perforated patch were employed to record fast response AP (fAP), slow response AP (sAP) and ionic currents in guinea pig papillary muscle or rabbit sinus node cells.Results: Tachyarrhythmia produced by isoprenaline (15 μmol/L) could be reversed by sophocarpine (300 μmol/L). Sophocarpine (10 μmol/L) decreased the amplitude by 4.0%, maximal depolarization velocity (Vmax) of the fAP by 24.4%, and Na+ current (INa) by 18.0%,while it prolonged the effective refractory period (ERP) by 21.1%. The same concentration of sophocarpine could also decrease the amplitude and Vmax of the sAP, by 26.8% and 25.7%, respectively, and attenuated the Ca2+ current (ICaL) and the K+ tail current substantially. Comparison of sophocarpine with amiodarone demonstrated that both prolonged the duration and the ERP of fAP and sAP, both decreased the amplitude and Vmax of the fAP and sAP, and both slowed the automatic heart rate.Conclusion: Sophocarpine could reverse isoprenaline-induced arrhythmia and inhibit INa, IcaL, and Ikr currents. The electrophysiological effects of sophocarpine are similar to those of amiodarone, which might be regarded as a prospective antiarrhythmic agent.

  10. Electrophysiological Characteristics of Embryonic Stem Cell-Derived Cardiomyocytes are Cell Line-Dependent

    Directory of Open Access Journals (Sweden)

    Tobias Hannes

    2015-01-01

    Full Text Available Background: Modelling of cardiac development, physiology and pharmacology by differentiation of embryonic stem cells (ESCs requires comparability of cardiac differentiation between different ESC lines. To investigate whether the outcome of cardiac differentiation is consistent between different ESC lines, we compared electrophysiological properties of ESC-derived cardiomyocytes (ESC-CMs of different murine ESC lines. Methods: Two wild-type (D3 and R1 and two transgenic ESC lines (D3/aPIG44 and CGR8/AMPIGX-7 were differentiated under identical culture conditions. The transgenic cell lines expressed enhanced green fluorescent protein (eGFP and puromycin-N-acetyltransferase under control of the cardiac specific α-myosin heavy chain (αMHC promoter. Action potentials (APs were recorded using sharp electrodes and multielectrode arrays in beating clusters of ESC-CMs. Results: Spontaneous AP frequency and AP duration (APD as well as maximal upstroke velocity differed markedly between unpurified CMs of the four ESC lines. APD heterogeneity was negligible in D3/aPIG44, moderate in D3 and R1 and extensive in CGR8/AMPIGX-7. Interspike intervals calculated from long-term recordings showed a high degree of variability within and between recordings in CGR8/AMPIGX-7, but not in D3/aPIG44. Purification of the αMHC+ population by puromycin treatment posed only minor changes to APD in D3/aPIG44, but significantly shortened APD in CGR8/AMPIGX-7. Conclusion: Electrophysiological properties of ESC-CMs are strongly cell line-dependent and can be influenced by purification of cardiomyocytes by antibiotic selection. Thus, conclusions on cardiac development, physiology and pharmacology derived from single stem cell lines have to be interpreted carefully.

  11. Drosophila KCNQ channel displays evolutionarily conserved electrophysiology and pharmacology with mammalian KCNQ channels.

    Directory of Open Access Journals (Sweden)

    Sonia Cavaliere

    Full Text Available Of the five human KCNQ (Kv7 channels, KCNQ1 with auxiliary subunit KCNE1 mediates the native cardiac I(Ks current with mutations causing short and long QT cardiac arrhythmias. KCNQ4 mutations cause deafness. KCNQ2/3 channels form the native M-current controlling excitability of most neurons, with mutations causing benign neonatal febrile convulsions. Drosophila contains a single KCNQ (dKCNQ that appears to serve alone the functions of all the duplicated mammalian neuronal and cardiac KCNQ channels sharing roughly 50-60% amino acid identity therefore offering a route to investigate these channels. Current information about the functional properties of dKCNQ is lacking therefore we have investigated these properties here. Using whole cell patch clamp electrophysiology we compare the biophysical and pharmacological properties of dKCNQ with the mammalian neuronal and cardiac KCNQ channels expressed in HEK cells. We show that Drosophila KCNQ (dKCNQ is a slowly activating and slowly-deactivating K(+ current open at sub-threshold potentials that has similar properties to neuronal KCNQ2/3 with some features of the cardiac KCNQ1/KCNE1 accompanied by conserved sensitivity to a number of clinically relevant KCNQ blockers (chromanol 293B, XE991, linopirdine and opener (zinc pyrithione. We also investigate the molecular basis of the differential selectivity of KCNQ channels to the opener retigabine and show a single amino acid substitution (M217W can confer sensitivity to dKCNQ. We show dKCNQ has similar electrophysiological and pharmacological properties as the mammalian KCNQ channels, allowing future study of physiological and pathological roles of KCNQ in Drosophila and whole organism screening for new modulators of KCNQ channelopathies.

  12. Stem cells for cardiac repair: an introduction

    Institute of Scientific and Technical Information of China (English)

    Bastiaan C du Pr(e); Pieter A Doevendans; Linda W van Laake

    2013-01-01

    Cardiovascular disease is a major cause of morbidity and mortality throughout the world. Most cardiovascular diseases, such as ischemic heart disease and cardiomyopathy, are associated with loss of functional cardiomyocytes. Unfortunately, the heart has a limited regenerative capacity and is not able to replace these cardiomyocytes once lost. In recent years, stem cells have been put forward as a potential source for cardiac regeneration. Pre-clinical studies that use stem cell-derived cardiac cells show promising results. The mechanisms, though, are not well understood, results have been variable, sometimes transient in the long term, and often without a mechanistic explanation. There are still several major hurdles to be taken. Stem cell-derived cardiac cells should resemble original cardiac cell types and be able to integrate in the damaged heart. Integration requires administration of stem cell-derived cardiac cells at the right time using the right mode of delivery. Once delivered, transplanted cells need vascularization, electrophysiological coupling with the injured heart, and prevention of immunological rejection. Finally, stem cell therapy needs to be safe, reproducible, and affordable. In this review, we will give an introduction to the principles of stem cell based cardiac repair.

  13. Electrophysiological research on conversation and discourse processing

    NARCIS (Netherlands)

    Hoeks, John; Brouwer, Harm; Holtgraves, Thomas

    2014-01-01

    Research into the electrophysiology of language comprehension has essentially been “speakerless.” This has left three vital aspects of communication—it is social, pragmatic, and dynamic—severely underresearched. This chapter makes a case for the investigation of language users involved in active con

  14. Electrophysiological study in neuromuscular junction disorders

    OpenAIRE

    Cherian, Ajith; Baheti, Neeraj N.; Iype, Thomas

    2013-01-01

    This review is on ultrastructure and subcellular physiology at normal and abnormal neuromuscular junctions. The clinical and electrophysiological findings in myasthenia gravis, Lambert-Eaton myasthenic syndrome (LEMS), congenital myasthenic syndromes, and botulinum intoxication are discussed. Single fiber electromyography (SFEMG) helps to explain the basis of testing neuromuscular junction function by repetitive nerve stimulation (RNS). SFEMG requires skill and patience and its availability i...

  15. Electrophysiological evaluation of psychogenic movement disorders.

    Science.gov (United States)

    Kamble, Nitish L; Pal, Pramod Kumar

    2016-01-01

    Psychogenic movement disorders (PMD) include a group of neurological symptoms which cannot be explained by any organic syndrome. The diagnosis of PMD is challenging for both neurologist and psychiatrist. Electrophysiological examination is a useful tool to evaluate and support a diagnosis PMD. It includes a set of tests which are chosen appropriate to the clinical setting that provides objective criteria for the diagnosis of PMD. The various tests available include accelerometry, surface electromyography, electroencephalography, jerk locked back averaging and pre-movement potentials, somatosensory evoked potentials, transcranial magnetic stimulation (TMS) etc. Electrophysiologically psychogenic tremors display features of variability, entrainability, coactivation, distractibility and increase in the amplitude and frequency on mass loading. Movement related cortical potentials such as Bereitschaftspotential is seen in psychogenic myoclonus. Presence of triphasic contraction of muscles and absence of co-contraction suggests psychogenic myoclonus. Latency of C-reflex is longer in psychogenic myoclonus as compared to organic myoclonus. The role of TMS to differentiate psychogenic from organic dystonia is still not clear. In conclusion, electrophysiological tests are most useful for tremor, followed by jerks and least for dystonia. In patients with long-standing PMD or those with mixed pathology, electrophysiological tests may not be very useful. PMID:26403429

  16. Cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Dewey, Marc [Charite - Universitaetsmedizin Berlin (Germany). Inst. fuer Radiologie

    2011-07-01

    Computed tomography of the heart has become a highly accurate diagnostic modality that is attracting increasing attention. This extensively illustrated book aims to assist the reader in integrating cardiac CT into daily clinical practice, while also reviewing its current technical status and applications. Clear guidance is provided on the performance and interpretation of imaging using the latest technology, which offers greater coverage, better spatial resolution, and faster imaging. The specific features of scanners from all four main vendors, including those that have only recently become available, are presented. Among the wide range of applications and issues to be discussed are coronary artery bypass grafts, stents, plaques, and anomalies, cardiac valves, congenital and acquired heart disease, and radiation exposure. Upcoming clinical uses of cardiac CT, such as plaque imaging and functional assessment, are also explored. (orig.)

  17. Cardiac echinococcosis

    Directory of Open Access Journals (Sweden)

    Ivanović-Krstić Branislava A.

    2002-01-01

    Full Text Available Cardiac hydatid disease is rare. We report on an uncommon hydatid cyst localized in the right ventricular wall, right atrial wall tricuspid valve left atrium and pericard. A 33-year-old woman was treated for cough, fever and chest pain. Cardiac echocardiograpic examination revealed a round tumor (5.8 x 4 cm in the right ventricular free wall and two smaller cysts behind that tumor. There were cysts in right atrial wall and tricuspidal valve as well. Serologic tests for hydatidosis were positive. Computed tomography finding was consistent with diagnosis of hydatid cyst in lungs and right hylar part. Surgical treatment was rejected due to great risk of cardiac perforation. Medical treatment with albendazole was unsuccessful and the patient died due to systemic hydatid involvement of the lungs, liver and central nervous system.

  18. Multifocal Ectopic Purkinje-Related Premature Contractions: A New SCN5A-Related Cardiac Channelopathy. : MEPPC: a new SCN5A-related cardiac channelopathy

    OpenAIRE

    Amarouch, Mohamed Yassine; Barc, Julien; Bar, Isabelle; Baron, Estelle; Barthez, Olivier; Bertaux, Geraldine; Béziau, Delphine M.; Charpentier, Flavien; Charron, Philippe; Coudière, Yves; Dina, Christian; Faivre, Laurence; Fressart, Véronique; Kyndt, Florence; Laurent, Gabriel

    2012-01-01

    OBJECTIVES: The aim of this study was to describe a new familial cardiac phenotype and to elucidate the electrophysiological mechanism responsible for the disease. BACKGROUND: Mutations in several genes encoding ion channels, especially SCN5A, have emerged as the basis for a variety of inherited cardiac arrhythmias. METHODS: Three unrelated families comprising 21 individuals affected by multifocal ectopic Purkinje-related premature contractions (MEPPC) characterized by narrow junctional and r...

  19. Comparison of Ventricular Electrophysiological Effects of Amiodarone in Canine Models With Congestive Heart Failure and Normal Dogs

    Institute of Scientific and Technical Information of China (English)

    Shuxian Zhou; Yuling Zhang; Juan Lei; Wei Wu; Xuming Zhang

    2008-01-01

    Objectives This study compared the effects of amiodarone on ventricular electrophysiological properties in normal dogs and CHF dogs.Methods Dogs(n=44) were randomized into four groups:Group 1(n=10)was the control.Group 2(n=10) was given amiodarone orally 300 mg·d-1 for4 to 5 weeks.Group 3(n=12)was the congestive heart failure(CHF)models induced by right ventricular rapid pacing(240 pulses·rain-1 for 4 to 5 weeks).Group 4 (n=12) was the CHF models given amiodarone orally 300 mg·d-1 for 4 to 5 weeks.The ventricular electrophysiological variables were evaluated by standard electric stimulation and monophasic action potential(MAP)recording.Results Amiodarone prolonged sinus cycle length(SCL),intra-ventricular conduction time(IVCT),MAP duration(MAPD90),ventricular effective period(VERP),ventricular activation time(VAT)and ventficular recovery time(VRT)without significant effects on the ratio of VERP to MAPD90 (VERP/MAPD90),ventricular fibrillation threshold(VFT),the dispersion of VRT(VRTD),and ventricular late repolarization duration(VLRD)in normal dogs.However,amiodarone did not further prolong the prolonged SCL,MAPD90,VERP,VAT and VRT,but further prolonged IVCT in CHF dogs.Amiodarone normalized the abnormal ventficular electrophysiological properties in CHF dogs as manifested by increasing the decreased VERP/MAPD90 and VFT,shortening the prolonged VLRD,and decreasing the increased VRTD.Amiodarone did not worsen the hemodynamic parameters in normal and CHF dogs.Conclusions Amiodarone had different effects on ventricular electrophysiological properties in normal and CHF dogs.The favorable effects of amiodarone in normalizing some abnormal cardiac electrophysiological properties in CHF models may have potential value on the prevention and treatment of ventricular arrhythmias and sudden cardiac death in CHF.

  20. [Cardiac amyloidosis].

    Science.gov (United States)

    Hoyer, Caroline; Angermann, Christiane E; Knop, Stefan; Ertl, Georg; Störk, Stefan

    2008-03-15

    Amyloidoses are a heterogeneous group of multisystem disorders, which are characterized by an extracellular deposition of amyloid fibrils. Typically affected are the heart, liver, kidneys, and nervous system. More than half of the patients die due to cardiac involvement. Clinical signs of cardiac amyloidosis are edema of the lower limbs, hepatomegaly, ascites and elevated jugular vein pressure, frequently in combination with dyspnea. There can also be chest pain, probably due to microvessel disease. Dysfunction of the autonomous nervous system or arrhythmias may cause low blood pressure, dizziness, or recurrent syncope. The AL amyloidosis caused by the deposition of immunoglobulin light chains is the most common form. It can be performed by monoclonal gammopathy. The desirable treatment therapy consists of high-dose melphalan therapy twice followed by autologous stem cell transplantation. Due to the high peritransplantation mortality, selection of appropriate patients is mandatory. The ATTR amyloidosis is an autosomal dominant disorder caused by the amyloidogenic form of transthyretin, a plasmaprotein that is synthesized in the liver. Therefore, liver transplantation is the only curative therapy. The symptomatic treatment of cardiac amyloidosis is based on the current guidelines for chronic heart failure according to the patient's New York Heart Association (NYHA) state. Further types of amyloidosis with possible cardiac involvement comprise the senile systemic amyloidosis caused by the wild-type transthyretin, secondary amyloidosis after chronic systemic inflammation, and the beta(2)-microglobulin amyloidosis after long-term dialysis treatment. PMID:18344065

  1. The radiation risks for patients undergoing electrophysiology treatment of atrial fibrillation

    International Nuclear Information System (INIS)

    Full text: Atrial Fibrillation (AF) Ablations are complex electrophysiology (EP) procedures that have the potential to deliver significant radiation risk to the patient. The nature of AF is such that many patients require more than one procedure before a 'successful' outcome is achieved. This analysis aims to provide a better understanding of the radiation risks involved in EP treatment of AF. Methods Records for imaging procedures performed between January 1997 and May 2011 were reviewed. Analysis identified 439 AF ablation procedures on 293 patients (71 % male, median age 58, range 21-85). In total, these patients underwent 866 separate cardiac diagnostic, interventional, electrophysiology and device implant procedures. Effective Dose (E) estimates were derived for all procedures. 35% of patients had> I AF procedure (I patient undergoing 5). Actuarial analysis suggests freedom from return for follow-up AF ablation at 5 years of 65%. Reviewing all cardiac imaging histories for the 293 patients shows 60% had> I procedure (5% having >4) and 44% underwent cardiac procedures other than AF ablations. E for individual procedures ranged to 28 mSv with cumulative E for AF and all cardiac procedures ranging to 38 mSv and 80 mSv respectively. Many patients also underwent CT procedures to acquire 3D datasets for use in AF ablations (risk not assessed here). These findings suggest that the true radiation risk associated with AF ablation treatment is greater than that reported for an individual procedure. Every effort must therefore be taken to pursue techniques and technologies that limit radiation risk in these procedures.

  2. Electrophysiological Changes of the Atrium in Patients with Lone Paroxysmal Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Osmar Antonio Centurion, MD, PhD, FACC

    2010-06-01

    Full Text Available Introduction : Paroxysmal atrial fibrillation (PAF is a common arrhythmia, and it is associated with various cardiac conditions. On the other hand, lone PAF has no identifiable underlying cause, and can occur any time for no apparent reason. The underlying causes may modify the electrophysiological properties of the atrium in different ways and extent. However this setting may be different in patients with lone PAF. We sought to investigate the atrial electrophysiological properties in lone PAF. Material and Methods : This study included 62 control subjects (Control group and 58 patients with lone PAF (LAF group. The following atrial vulnerability parameters induced by programmed atrial stimulation were assessed and quantitatively measured: 1 the atrial effective refractory period (ERP, 2 the atrial conduction delay (CD zone, and 3 the maximum CD. Results : The mean atrial ERP of the Control group was 215±29 ms, and that of LAF group was 208±28 ms, p<0.05. The mean atrial CD zone of the LAF group was (50±28 ms significantly greater than that of controls (34±22 ms (p<0.01. The mean maximum CD of the LAF group (62±29 ms was also significantly greater than that of controls (43±20 ms (p<0.01. Conclusions : There is a greater conduction delay of the atrium and shorter refractoriness in patients with lone PAF. Patients without underlying causes for the development of PAF exhibit abnormalities in the electrophysiological properties of the atrium.

  3. Direct-growth carbon nanotubes on 3D structural microelectrodes for electrophysiological recording.

    Science.gov (United States)

    Pan, Alice Ian; Lin, Min-Hsuan; Chung, Hui-Wen; Chen, Hsin; Yeh, Shih-Rung; Chuang, Yung-Jen; Chang, Yen-Chung; Yew, Tri-Rung

    2016-01-01

    A novel 3D carbon nanotube (CNT) microelectrode was developed through direct growth of CNTs on a gold pin-shaped 3D microelectrode at a low temperature (400 °C) for applications in neural and cardiac recording. With an electroplated Ni catalyst layer covering the entire surface of the pin-shaped structure, CNTs were synthesized on a 3D microelectrode by catalytic thermal chemical vapor deposition (CVD). According to the analyses by electrochemical impedance spectroscopy, the impedance of 3D microelectrodes after CNT growth and UV/O3 treatment decreased from 9.3 Ω mm(-2) to 1.2 Ω mm(-2) and the capacitance increased largely from 2.2 mF cm(-2) to 73.3 mF cm(-2). The existence of UVO3-treated CNT led to a large improvement of interfacial capacitance, contributing to the decrease of impedance. The electrophysiological detection capability of this 3D CNT microelectrode was demonstrated by the distinguished P waves, QRS complex and T waves in the electrocardiogram of the zebrafish heart and the action potential recorded from individual rat hippocampal neurons. The compatibility of integration with ICs, high resolution in space, electrophysiological signals, and non-invasive long-term recording suggest that the 3D CNT microelectrode exhibits promising potential for applications in electrophysiological research and clinical trials.

  4. Role of electrophysiological study in patients with syncope and bundle branch block

    Directory of Open Access Journals (Sweden)

    Neshat Nazari

    2014-01-01

    Full Text Available Background: The finding of bundle branch block (BBB in patients with syncope suggests that paroxysmal atrioventricular block (AVB or ventricular tachyarrhythmia (VT may be the cause of syncope. Guidelines for cardiac pacing and cardiac resynchronization therapy have been recommended to perform electrophysiological study (EPS for confirming main cause of syncope. Therefore, the aim of our study was to evaluate the role of EPS in patients with syncope and BBB. Materials and Methods: We evaluated 133 patients (mean age 63 ± 13.8 years with past history of syncope and BBB from April 2002 to December 2010 who referred to Arrhythmia clinic in two tertiary care centers. All patients underwent EPS on admission time. The frequency distributions of AVB and VT in patients were determined. Results: Left bundle branch block was diagnosed in 184 (82.1% patients. 133 of them had preserved left ventricular ejection fraction (LVEF ≥45% that in 91 (68.4% of those, EPS finding was normal. In 41 (30.8% patients AVB was reported. In 2 (1.5% patients VT and atrioventricular nodal reentrant tachycardia were seen. Coronary artery disease was more common in patients with AVB and abnormal EPS finding (P = 0.02. Conclusion: Ventricular tachyarrhythmia was a rare electrophysiological finding in those with syncope, bifascicular block, and preserved LVEF. Considering cost-effect benefit, pacemaker or implantable loop recorder implantation is suggested; however, EPS may not be necessary to perform before permanent pacemaker implantation.

  5. Python for large-scale electrophysiology

    Directory of Open Access Journals (Sweden)

    Martin A Spacek

    2009-01-01

    Full Text Available Electrophysiology is increasingly moving towards highly parallel recording techniques which generate large data sets. We record extracellularly in vivo in cat and rat visual cortex with 54 channel silicon polytrodes, under time-locked visual stimulation, from localized neuronal populations within a cortical column. To help deal with the complexity of generating and analyzing these data, we used the Python programming language to develop three software projects: one for temporally precise visual stimulus generation (dimstim; one for electrophysiological waveform visualization and spike sorting (spyke; and one for spike train and stimulus analysis (neuropy. All three are open source and available for download (http://swindale.ecc.ubc.ca/code. The requirements and solutions for these projects differed greatly, yet we found Python to be well suited for all three. Here we present our software as a showcase of the extensive capabilities of Python in neuroscience.

  6. On the electrophysiology of aesthetic processing.

    Science.gov (United States)

    Jacobsen, Thomas

    2013-01-01

    One important method that can be applied for gaining an understanding of the underpinning of aesthetics in the brain is that of electrophysiology. Cognitive electrophysiology, in particular, allows the identification of components in a mental processing architecture. The present chapter reviews findings in the neurocognitive psychology of aesthetics, or neuroaesthetics, that have been obtained with the method of event-related brain potentials, as derived from the human electroencephalogram. The cognitive-perceptual bases as well as affective substages of aesthetic processing have been investigated and those are described here. The event-related potential method allows for the identification of mental processing modes in cognitive and aesthetic processing. It also provides an assessment of the mental chronometry of cognitive and affective stages in aesthetic appreciation. As the work described here shows, distinct processes in the brain are engaged in aesthetic judgments. PMID:24041323

  7. Python for large-scale electrophysiology.

    Science.gov (United States)

    Spacek, Martin; Blanche, Tim; Swindale, Nicholas

    2008-01-01

    Electrophysiology is increasingly moving towards highly parallel recording techniques which generate large data sets. We record extracellularly in vivo in cat and rat visual cortex with 54-channel silicon polytrodes, under time-locked visual stimulation, from localized neuronal populations within a cortical column. To help deal with the complexity of generating and analysing these data, we used the Python programming language to develop three software projects: one for temporally precise visual stimulus generation ("dimstim"); one for electrophysiological waveform visualization and spike sorting ("spyke"); and one for spike train and stimulus analysis ("neuropy"). All three are open source and available for download (http://swindale.ecc.ubc.ca/code). The requirements and solutions for these projects differed greatly, yet we found Python to be well suited for all three. Here we present our software as a showcase of the extensive capabilities of Python in neuroscience.

  8. [Fundamental ophthalmology: the role of electrophysiological studies].

    Science.gov (United States)

    Zueva, M V

    2014-01-01

    Studying of functional aspects of eye disease pathogenesis by electrophysiological methods is widely demanded in fundamental ophthalmology. Introduction of modern methods of functional assessment into experimental and clinical projects significantly broadens knowledge of normal and pathological functioning of the visual system and is the basis for further development of new strategies of pathogenetic treatment, diagnostics and expert evaluation. Some problems of ophthalmology, including those that concern age-related macular degeneration, glaucoma, diabetic retinopathy, and other diseases, are considered in the context of how much electrophysiology contributes to their solution. The role of functional examinations of the retina in studying pathophysiology of neurodegenerative brain diseases, such as Alzheimer's and Parkinson's, is also discussed. PMID:25715550

  9. Effects of irbesartan on atrial cell electrophysiology

    Institute of Scientific and Technical Information of China (English)

    HUANG Cong-xin; CAO Feng; JIANG Hong; WANG Teng; LI Xia

    2005-01-01

    @@ Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice.1 Its incidence increases with age and the presence of structural heart disease. It is a major cause of stroke, especially in the elderly. It has been shown that angiotensin converting enzyme inhibitor (ACEI) can reduce the incidence of AF after acute myocardial infarction.2 Several studies have shown that activation of the rennin-angiotensin system is associated with the mechanisms of AF. Irbesartan is a long-acting angiotensin Ⅱ type 1 receptor antagonist used widely in the treatment of hypertension.3 In recent years, it has been demonstrated that patients treated with amiodarone plus irbesartan had a lower rate of recurrence of atrial fibrillation than did patients treated with amiodarone alone.4 These findings suggest that the inhibition of angiotensin Ⅱ may prevent AF, but its underlying electrophysiological mechanisms are obscure. The purpose of this study is to investigate the effects of irbesartan on atrial cell electrophysiology.

  10. Prevention of Pazopanib-Induced Prolonged Cardiac Repolarization and Proarrhythmic Effects

    OpenAIRE

    Tulay Akman; Oytun Erbas; Levent Akman; Yilmaz, Ahmet U.

    2014-01-01

    Background: Pazopanib (PZP) may induce prolonged cardiac repolarization and proarrhythmic effects, similarly to other tyrosine kinase inhibitors. Objectives: To demonstrate PZP-induced prolonged cardiac repolarization and proarrhythmic electrophysiological effects and to investigate possible preventive effects of metoprolol and diltiazem on ECG changes (prolonged QT) in an experimental rat model. Methods: Twenty-four Sprague-Dawley adult male rats were randomly assigned to 4 groups (n = 6...

  11. Oyster Electrophysiology: Electrocardiogram Signal Recognition and Interpretation

    OpenAIRE

    Frederico M Batista; Deborah M Power; Harrison, Adrian P.

    2015-01-01

    After 100 years of published recording traces pertaining to the oyster electrocardiogram (ECG), we revisited the original experiments of Eiger (1913), using state-of-the-art electrophysiology recorders. Our aim was to confirm that a recordable ECG, similar to that of higher vertebrates, is present in the oyster heart. Portuguese oysters Crassostrea angulata, collected from the Guadiana estuary, Portugal, were used. The oysters were drilled through the right valve to reveal the pericardium. Go...

  12. Comprehensive multilevel in vivo and in vitro analysis of heart rate fluctuations in mice by ECG telemetry and electrophysiology.

    Science.gov (United States)

    Fenske, Stefanie; Pröbstle, Rasmus; Auer, Franziska; Hassan, Sami; Marks, Vanessa; Pauza, Danius H; Biel, Martin; Wahl-Schott, Christian

    2016-01-01

    The normal heartbeat slightly fluctuates around a mean value; this phenomenon is called physiological heart rate variability (HRV). It is well known that altered HRV is a risk factor for sudden cardiac death. The availability of genetic mouse models makes it possible to experimentally dissect the mechanism of pathological changes in HRV and its relation to sudden cardiac death. Here we provide a protocol that allows for a comprehensive multilevel analysis of heart rate (HR) fluctuations. The protocol comprises a set of techniques that include in vivo telemetry and in vitro electrophysiology of intact sinoatrial network preparations or isolated single sinoatrial node (SAN) cells. In vitro preparations can be completed within a few hours, with data acquisition within 1 d. In vivo telemetric ECG requires 1 h for surgery and several weeks for data acquisition and analysis. This protocol is of interest to researchers investigating cardiovascular physiology and the pathophysiology of sudden cardiac death.

  13. Cardiac rhabdomyosarcoma

    OpenAIRE

    Chlumský, Jaromír; Holá, Dana; Hlaváček, Karel; Michal, Michal; Švec, Alexander; Špatenka, Jaroslav; Dušek, Jan

    2001-01-01

    Cardiac sarcoma is a very rare neoplasm and is difficult to diagnose. The case of a 51-year-old man with a left atrial tumour, locally recurrent three months after its surgical removal, is presented. Computed tomography showed metastatic spread to the lung parenchyma. On revised histology, the mass extirpated was a sarcoma. Because of the metastatic spread, further therapy was symptomatic only; the patient died 15 months after the first manifestation of his problems. Immunohistochemical stain...

  14. Implementation of Contraction to Electrophysiological Ventricular Myocyte Models, and Their Quantitative Characterization via Post-Extrasystolic Potentiation.

    Directory of Open Access Journals (Sweden)

    Yanyan Claire Ji

    Full Text Available Heart failure (HF affects over 5 million Americans and is characterized by impairment of cellular cardiac contractile function resulting in reduced ejection fraction in patients. Electrical stimulation such as cardiac resynchronization therapy (CRT and cardiac contractility modulation (CCM have shown some success in treating patients with HF. Computer simulations have the potential to help improve such therapy (e.g. suggest optimal lead placement as well as provide insight into the underlying mechanisms which could be beneficial. However, these myocyte models require a quantitatively accurate excitation-contraction coupling such that the electrical and contraction predictions are correct. While currently there are close to a hundred models describing the detailed electrophysiology of cardiac cells, the majority of cell models do not include the equations to reproduce contractile force or they have been added ad hoc. Here we present a systematic methodology to couple first generation contraction models into electrophysiological models via intracellular calcium and then compare the resulting model predictions to experimental data. This is done by using a post-extrasystolic pacing protocol, which captures essential dynamics of contractile forces. We found that modeling the dynamic intracellular calcium buffers is necessary in order to reproduce the experimental data. Furthermore, we demonstrate that in models the mechanism of the post-extrasystolic potentiation is highly dependent on the calcium released from the Sarcoplasmic Reticulum. Overall this study provides new insights into both specific and general determinants of cellular contractile force and provides a framework for incorporating contraction into electrophysiological models, both of which will be necessary to develop reliable simulations to optimize electrical therapies for HF.

  15. Implementation of Contraction to Electrophysiological Ventricular Myocyte Models, and Their Quantitative Characterization via Post-Extrasystolic Potentiation.

    Science.gov (United States)

    Ji, Yanyan Claire; Gray, Richard A; Fenton, Flavio H

    2015-01-01

    Heart failure (HF) affects over 5 million Americans and is characterized by impairment of cellular cardiac contractile function resulting in reduced ejection fraction in patients. Electrical stimulation such as cardiac resynchronization therapy (CRT) and cardiac contractility modulation (CCM) have shown some success in treating patients with HF. Computer simulations have the potential to help improve such therapy (e.g. suggest optimal lead placement) as well as provide insight into the underlying mechanisms which could be beneficial. However, these myocyte models require a quantitatively accurate excitation-contraction coupling such that the electrical and contraction predictions are correct. While currently there are close to a hundred models describing the detailed electrophysiology of cardiac cells, the majority of cell models do not include the equations to reproduce contractile force or they have been added ad hoc. Here we present a systematic methodology to couple first generation contraction models into electrophysiological models via intracellular calcium and then compare the resulting model predictions to experimental data. This is done by using a post-extrasystolic pacing protocol, which captures essential dynamics of contractile forces. We found that modeling the dynamic intracellular calcium buffers is necessary in order to reproduce the experimental data. Furthermore, we demonstrate that in models the mechanism of the post-extrasystolic potentiation is highly dependent on the calcium released from the Sarcoplasmic Reticulum. Overall this study provides new insights into both specific and general determinants of cellular contractile force and provides a framework for incorporating contraction into electrophysiological models, both of which will be necessary to develop reliable simulations to optimize electrical therapies for HF. PMID:26317204

  16. The incidence of sudden cardiac death in athletes

    Directory of Open Access Journals (Sweden)

    Popović Dejana

    2006-01-01

    Full Text Available Introduction. Despite remarkable advances in medicine and sports, sudden cardiac death remains a significant problem. Incidence of sudden cardiac death. The incidence of sudden cardiac death varies in different studies and there are no systematic data about it. It varies in different types of sports, with age and sex. Sudden cardiac death and physical activity. Many changes in cardiac morphology and function represent an adaptive response to physical activity. As a result, the heart undergoes profound morphologic, functional and electro-physiological alterations. But as there are different kinds of physical activities, the degree of these morphological changes is highly variable. It is needless to say how important it is to know which changes in the heart due to physical activity are normal, and when they are pathological. Considering the results of many studies, the main cause of sudden cardiac death is hypertrophic cardiomiopathy. Conclusion. It is very important to distinguish physiological changes of the heart due to physical activity, and pathological changes due to some cardiac diseases. That is why, clear recommendations on intensity, type, duration and frequency of physical training in every sports discipline are necessary. That is the only way to decrease the incidence of sudden cardiac death in athletes. .

  17. The earliest electrophysiological correlate of visual awareness?

    DEFF Research Database (Denmark)

    Koivisto, Mika; Lähteenmäki, Mikko; Sørensen, Thomas Alrik;

    2008-01-01

    To examine the neural correlates and timing of human visual awareness, we recorded event-related potentials (ERPs) in two experiments while the observers were detecting a grey dot that was presented near subjective threshold. ERPs were averaged for conscious detections of the stimulus (hits...... of attention. The early negativity, called 'visual awareness negativity' (VAN), may be a general, primary electrophysiological correlate of visual awareness. The present data show that it can be observed in response to appearance of a stimulus in visual awareness and that it generalizes across different...

  18. Morphological and electrophysiological properties of single myocardial cells from Koch triangle of rabbit heart

    Institute of Scientific and Technical Information of China (English)

    REN Fu-xian; NIU Xiao-lin; OU Yan; HAN Zhen-hua; LING Feng-dong; ZHOU Shi-sheng; LI Ya-jie

    2006-01-01

    Background The morphological and electrophysiological characteristics of cardiac cells in Koch triangle are still disputed. We studied the appearance and electrical properties of these diverse myocytes to elucidate their complex electrophysiological phenomena.Methods Experiments were conducted using cooled charge coupling device (CCD) system and whole cell,patch clamp technique to determine the morphology, action potential and sodium current density of single viable myocytes enzymatically isolated from the Koch triangle of rabbit hearts.Results Morphologically, cardiac cells in shape of spider, tiny spindle, slender spindle, rod and strip were observed in percentage of 3.0±0.3, 35.0±5.0, 15.0±2.0, 40.0±5.0 and 6.0±0.7 respectively. The cellular dimensions and capacitance gradually increased in the above order (all P<0.05). Electrophysiologically, action potential configurations recorded from them were similar respectively to nodal (N), atrial nodal (AN), nodal Hisian (NH), atrial (A) and Hisian like potentials obtained from the intact atrioventricular nodal preparations.Diastolic depolarization appeared in all myocytes except for rod cells. Sodium current density increased in the order of tiny spindle, strip, rod, slender spindle cell (all P<0.05), but could not be detected in spider-shaped cells.Linear regression analysis revealed that membrane capacitance was correlated negatively to the rate of diastolic depolarization r=-0.70, P<0.001, but positively to maximum depolarization potential, amplitude of action potential, upstroke velocity and maximum peak value of sodium current density r=-0.84, 0.80, 0.87 and 0.75,respectively; all P<0.001.Conclusions The results demonstrated that spider-shaped, spindle, rod and strip cells in Koch triangle might correspond to pacemaking, transitional, atrial and Purkinje like cells, respectively. Furthermore, tiny spindle and slender spindle cells were referred to transitional cell α (TCα) and β (TCβ) accordingly

  19. Utility of electrophysiological studies to predict arrhythmic events

    Institute of Scientific and Technical Information of China (English)

    Gabriela; Hilfiker; Andreas; W; Schoenenberger; Paul; Erne; Richard; Kobza

    2015-01-01

    AIM:To evaluate the prognostic value of electrophysiological stimulation(EPS) in the risk stratification for tachyarrhythmic events and sudden cardiac death(SCD).METHODS:We conducted a prospective cohort study and analyzed the long-term follow-up of 265 consecutive patients who underwent programmed ventricular stimulation at the Luzerner Kantonsspital(Lucerne,Switzerland) between October 2003 and April 2012. Patients underwent EPS for SCD risk evaluation because of structural or functional heart disease and/or electrical conduction abnormality and/or after syncope/cardiac arrest. EPS was considered abnormal,if a sustained ventricular tachycardia(VT) was inducible. The primary endpoint of the study was SCD or,in implanted patients,adequate ICD-activation.RESULTS:During EPS,sustained VT was induced in 125 patients(47.2%) and non-sustained VT in 60 patients(22.6%); in 80 patients(30.2%) no arrhythmia could be induced. In our cohort,153 patients(57.7%) underwent ICD implantation after the EPS. During follow-up(mean duration 4.8 ± 2.3 years),a primary endpoint event occurred in 49 patients(18.5%). The area under the receiver operating characteristic curve(AUROC) was 0.593(95%CI:0.515-0.670) for a left ventricular ejection fraction(LVEF) < 35% and 0.636(95%CI:0.563-0.709) for inducible sustained VT during EPS. The AUROC of EPS was higher in the subgroup of patients with LVEF ≥ 35%(0.681,95%CI:0.578-0.785). Cox regression analysis showed that both,sustained VT during EPS(HR:2.26,95%CI:1.22-4.19,P = 0.009) and LVEF < 35%(HR:2.00,95%CI:1.13-3.54,P = 0.018) were independent predictors of primary endpoint events.CONCLUSION:EPS provides a benefit in risk stratificationfor future tachyarrhythmic events and SCD and should especially be considered in patients with LVEF ≥ 35%.

  20. Electrophysiology of autonomic neuromuscular transmission involving ATP.

    Science.gov (United States)

    Sneddon, P

    2000-07-01

    Electrophysiological investigations of autonomic neuromuscular transmission have provided great insights into the role of ATP as a neurotransmitter. Burnstock and Holman made the first recordings of excitatory junction potentials (e.j.p.s) produced by sympathetic nerves innervating the smooth muscle of the guinea-pig vas deferens. This led to the identification of ATP as the mediator of e.j.p.s in this tissue, where ATP acts as a cotransmitter with noradrenaline. The e.j.p.s are mediated solely by ATP acting on P2X(1) receptors leading to action potentials and a rapid phasic contraction, whilst noradrenaline mediates a slower, tonic contraction which is not dependent on membrane depolarisation. Subsequent electrophysiological studies of the autonomic innervation of smooth muscles of the urogenital, gastrointestinal and cardiovascular systems have revealed a similar pattern of response, where ATP mediates a fast electrical and mechanical response, whilst another transmitter such as noradrenaline, acetylcholine, nitric oxide or a peptide mediates a slower response. The modulation of junction potentials by a variety of pre-junctional receptors and the mechanism of inactivation of ATP as a neurotransmitter will also be described.

  1. Diet-induced pre-diabetes slows cardiac conductance and promotes arrhythmogenesis

    DEFF Research Database (Denmark)

    Axelsen, Lene Nygaard; Callø, Kirstine; Braunstein, Thomas Hartig;

    2015-01-01

    a significant increase in cardiac triglyceride content (1.93 ± 0.19 (n = 12) vs. 0.77 ± 0.13 nmol/mg (n = 12), p cause electrophysiological changes, which leads to QRS prolongation, decreased conduction velocity and increased arrhythmogenesis during......BACKGROUND: Type 2 diabetes is associated with abnormal electrical conduction and sudden cardiac death, but the pathogenic mechanism remains unknown. This study describes electrophysiological alterations in a diet-induced pre-diabetic rat model and examines the underlying mechanism. METHODS....... Conduction velocity was examined in isolated tissue strips. Ion channel and gap junction conductances were analyzed by patch-clamp studies in isolated cardiomyocytes. Fibrosis was examined by Masson's Trichrome staining and thin-layer chromatography was used to analyze cardiac lipid content. Connexin43 (Cx43...

  2. Cardiac MRI in Athletes

    NARCIS (Netherlands)

    Luijkx, T.

    2012-01-01

    Cardiac magnetic resonance imaging (CMR) is often used in athletes to image cardiac anatomy and function and is increasingly requested in the context of screening for pathology that can cause sudden cardiac death (SCD). In this thesis, patterns of cardiac adaptation to sports are investigated with C

  3. Electrophysiological characterisation of KCNQ channel modulators

    DEFF Research Database (Denmark)

    Schrøder, R.L

    , spinal cord, and epithelial cells. Specific members of this subfamily regulate neuronal excitability (through the M-current), contribute to cardiac action potential repolarisation (through the IKs-current), mediate basolateral cAMP-dependent K+ conductance important for epithelial secretion...

  4. Developing a novel comprehensive framework for the investigation of cellular and whole heart electrophysiology in the in situ human heart: historical perspectives, current progress and future prospects.

    Science.gov (United States)

    Taggart, Peter; Orini, Michele; Hanson, Ben; Hayward, Martin; Clayton, Richard; Dobrzynski, Halina; Yanni, Joseph; Boyett, Mark; Lambiase, Pier D

    2014-08-01

    Understanding the mechanisms of fatal ventricular arrhythmias is of great importance. In view of the many electrophysiological differences that exist between animal species and humans, the acquisition of basic electrophysiological data in the intact human heart is essential to drive and complement experimental work in animal and in-silico models. Over the years techniques have been developed to obtain basic electrophysiological signals directly from the patients by incorporating these measurements into routine clinical procedures which access the heart such as cardiac catheterisation and cardiac surgery. Early recordings with monophasic action potentials provided valuable information including normal values for the in vivo human heart, cycle length dependent properties, the effect of ischaemia, autonomic nervous system activity, and mechano-electric interaction. Transmural recordings addressed the controversial issue of the mid myocardial "M" cell. More recently, the technique of multielectrode mapping (256 electrodes) developed in animal models has been extended to humans, enabling mapping of activation and repolarisation on the entire left and right ventricular epicardium in patients during cardiac surgery. Studies have examined the issue of whether ventricular fibrillation was driven by a "mother" rotor with inhomogeneous and fragmented conduction as in some animal models, or by multiple wavelets as in other animal studies; results showed that both mechanisms are operative in humans. The simpler spatial organisation of human VF has important implications for treatment and prevention. To link in-vivo human electrophysiological mapping with cellular biophysics, multielectrode mapping is now being combined with myocardial biopsies. This technique enables region-specific electrophysiology changes to be related to underlying cellular biology, for example: APD alternans, which is a precursor of VF and sudden death. The mechanism is incompletely understood but related

  5. Developing a novel comprehensive framework for the investigation of cellular and whole heart electrophysiology in the in situ human heart: historical perspectives, current progress and future prospects.

    Science.gov (United States)

    Taggart, Peter; Orini, Michele; Hanson, Ben; Hayward, Martin; Clayton, Richard; Dobrzynski, Halina; Yanni, Joseph; Boyett, Mark; Lambiase, Pier D

    2014-08-01

    Understanding the mechanisms of fatal ventricular arrhythmias is of great importance. In view of the many electrophysiological differences that exist between animal species and humans, the acquisition of basic electrophysiological data in the intact human heart is essential to drive and complement experimental work in animal and in-silico models. Over the years techniques have been developed to obtain basic electrophysiological signals directly from the patients by incorporating these measurements into routine clinical procedures which access the heart such as cardiac catheterisation and cardiac surgery. Early recordings with monophasic action potentials provided valuable information including normal values for the in vivo human heart, cycle length dependent properties, the effect of ischaemia, autonomic nervous system activity, and mechano-electric interaction. Transmural recordings addressed the controversial issue of the mid myocardial "M" cell. More recently, the technique of multielectrode mapping (256 electrodes) developed in animal models has been extended to humans, enabling mapping of activation and repolarisation on the entire left and right ventricular epicardium in patients during cardiac surgery. Studies have examined the issue of whether ventricular fibrillation was driven by a "mother" rotor with inhomogeneous and fragmented conduction as in some animal models, or by multiple wavelets as in other animal studies; results showed that both mechanisms are operative in humans. The simpler spatial organisation of human VF has important implications for treatment and prevention. To link in-vivo human electrophysiological mapping with cellular biophysics, multielectrode mapping is now being combined with myocardial biopsies. This technique enables region-specific electrophysiology changes to be related to underlying cellular biology, for example: APD alternans, which is a precursor of VF and sudden death. The mechanism is incompletely understood but related

  6. Na/K pump regulation of cardiac repolarization: insights from a systems biology approach

    KAUST Repository

    Bueno-Orovio, Alfonso

    2013-05-15

    The sodium-potassium pump is widely recognized as the principal mechanism for active ion transport across the cellular membrane of cardiac tissue, being responsible for the creation and maintenance of the transarcolemmal sodium and potassium gradients, crucial for cardiac cell electrophysiology. Importantly, sodium-potassium pump activity is impaired in a number of major diseased conditions, including ischemia and heart failure. However, its subtle ways of action on cardiac electrophysiology, both directly through its electrogenic nature and indirectly via the regulation of cell homeostasis, make it hard to predict the electrophysiological consequences of reduced sodium-potassium pump activity in cardiac repolarization. In this review, we discuss how recent studies adopting the systems biology approach, through the integration of experimental and modeling methodologies, have identified the sodium-potassium pump as one of the most important ionic mechanisms in regulating key properties of cardiac repolarization and its rate dependence, from subcellular to whole organ levels. These include the role of the pump in the biphasic modulation of cellular repolarization and refractoriness, the rate control of intracellular sodium and calcium dynamics and therefore of the adaptation of repolarization to changes in heart rate, as well as its importance in regulating pro-arrhythmic substrates through modulation of dispersion of repolarization and restitution. Theoretical findings are consistent across a variety of cell types and species including human, and widely in agreement with experimental findings. The novel insights and hypotheses on the role of the pump in cardiac electrophysiology obtained through this integrative approach could eventually lead to novel therapeutic and diagnostic strategies. © 2013 Springer-Verlag Berlin Heidelberg.

  7. Comparação de parâmetros eletrofisiológicos das estimulações cardíacas endocárdicas septal e apical Comparison of electrophysiological parameters of septal and apical endocardial cardiac stimulation

    Directory of Open Access Journals (Sweden)

    Juan Carlos Pachón Mateos

    2012-06-01

    pacing leads QRS widening and desynchronization myocardial compromising ventricular function. With the need for stimulation less deleterious, RV septal pacing has been used more. Eventually have been reported higher thresholds and smaller R waves in the septal stimulation. OBJECTIVE: To compare the parameters of the septal and apical stimulation, intra-patient, if there are any differences that may affect the choice of the point of stimulation. METHODS: A prospective controlled study. We included 25 patients, 67.2±9 years, 10 (40% women with indications for pacemaker for bradyarrhythmias. Etiologies were degenerative in nine (36%, Coronary disease in eight (32%, Chagas disease in seven (28%, and valve disease in one (4% patient. Electrodes were active fixation and assessed the thresholds of command, impedance and R wave in uniand bipolar implant and after six months. RESULTS: The average acute threshold command, R wave and impedance unipolar / bipolar septais x apicais were respectively 0.73 x 0.73V and 0,74V x 0,78V; 10 x 9,9mV and 12,3 x 12,4mV; 579 x 621Ω and 611 x 629Ω. Comparisons between parameters with septal and apical two-tailed paired t-test showed a P > 0.1. After six months, the mean control thresholds, R wave impedances and unipolar/bipolar septais x apicais were respectively 0.5V x 0 72V and 0.71V x 0,87V; 11.4 x 9,5mV and 12x11,2mV; 423x426 Ω and 578x550 Ω, with P > 0.05, except compared to unipolar pacing threshold septal apical unipolar P 0.02. CONCLUSION: Using intra-patient comparisons, no significant differences between electrophysiological parameters septal and apical pacing and there are no restrictions for choosing the right ventricular septal pacing.

  8. Electrophysiological and structural remodeling in heart failure modulate arrhythmogenesis. 2D simulation study.

    Directory of Open Access Journals (Sweden)

    Juan F Gomez

    Full Text Available Heart failure is operationally defined as the inability of the heart to maintain blood flow to meet the needs of the body and it is the final common pathway of various cardiac pathologies. Electrophysiological remodeling, intercellular uncoupling and a pro-fibrotic response have been identified as major arrhythmogenic factors in heart failure.In this study we investigate vulnerability to reentry under heart failure conditions by incorporating established electrophysiological and anatomical remodeling using computer simulations.The electrical activity of human transmural ventricular tissue (5 cm × 5 cm was simulated using the human ventricular action potential model Grandi et al. under control and heart failure conditions. The MacCannell et al. model was used to model fibroblast electrical activity, and their electrotonic interactions with myocytes. Selected degrees of diffuse fibrosis and variations in intercellular coupling were considered and the vulnerable window (VW for reentry was evaluated following cross-field stimulation.No reentry was observed in normal conditions or in the presence of HF ionic remodeling. However, defined amount of fibrosis and/or cellular uncoupling were sufficient to elicit reentrant activity. Under conditions where reentry was generated, HF electrophysiological remodeling did not alter the width of the VW. However, intermediate fibrosis and cellular uncoupling significantly widened the VW. In addition, biphasic behavior was observed, as very high fibrotic content or very low tissue conductivity hampered the development of reentry. Detailed phase analysis of reentry dynamics revealed an increase of phase singularities with progressive fibrotic components.Structural remodeling is a key factor in the genesis of vulnerability to reentry. A range of intermediate levels of fibrosis and intercellular uncoupling can combine to favor reentrant activity.

  9. Clinically and electrophysiologically diagnosed botulinum intoxication.

    Science.gov (United States)

    Kotan, Dilcan; Aygul, Recep; Ceylan, Mustafa; Yilikoglu, Yalcin

    2013-01-03

    In this case report, clinical and electrophysiological findings of 43-year-old female patient who developed Clostridium botulinum intoxication after consumption of home-made canned food are presented. Following the sudden onset of severe nausea and vomiting, diplopia, blurred vision, bilateral ptosis, weakness, speech and swallowing difficulties have developed and the patient declared that she has just tasted the canned beans after she had rinsed them several times. The case, where serological tests cannot be performed, was diagnosed clinically and treated with antitoxin immediately. During follow-up, consecutive nerve stimulation was performed and significant incremental response was observed. There was an improvement in symptoms within 2 weeks, and in 5 or 6 weeks the symptoms had disappeared completely. Electrodiagnostic studies revealed that the findings turned to normal. The case showed that immediate antitoxin treatment is life-saving even the diagnosis of botulinum intoxication is based on clinical findings.

  10. M-sequences in ophthalmic electrophysiology.

    Science.gov (United States)

    Müller, Philipp L; Meigen, Thomas

    2016-01-01

    The aim of this review is to use the multimedia aspects of a purely digital online publication to explain and illustrate the highly capable technique of m-sequences in multifocal ophthalmic electrophysiology. M-sequences have been successfully applied in clinical routines during the past 20 years. However, the underlying mathematical rationale is often daunting. These mathematical properties of m-sequences allow one not only to separate the responses from different fields but also to analyze adaptational effects and impacts of former events. By explaining the history, the formation, and the different aspects of application, a better comprehension of the technique is intended. With this review we aim to clarify the opportunities of m-sequences in order to motivate scientists to use m-sequences in their future research. PMID:26818968

  11. [Biofeedback in psychomotor training. Electrophysiological bases].

    Science.gov (United States)

    Bazanova, O M; Mernaia, E M; Shtark, M B

    2008-05-01

    Comparison of influence of usual musical practice and the same trainings but using biofeedback on electrophysiological and psychological markers of optimal psychomotor functioning in 39 students-musicians revealed that the obvious musical practice caused psychomotor pressure in most students (with initially low individual alpha peak frequency), whereas similar practice combined with an individualized session of alpha-EEG/EMG biofeedback was accompanied by increase of alpha-activity in all examinees and a decrease (reduction) of integrated EMG that indicated reaching of optimal psychomotor functioning. It appears that the psychomotor learning ability depends on the baseline individual alpha-activity. Individual alpha peak frequency was associated with fluency and efficiency of psychomotor performance, individual alpha band width--with plasticity and creativity, individual amount of alpha suppression in response to opening eyes--with the level of selfactualization. These alpha activity EEG indices correlated with efficiency of the biofeedback training. PMID:18669359

  12. Xenopus oocyte electrophysiology in GPCR drug discovery

    DEFF Research Database (Denmark)

    Hansen, Kasper Bø; Bräuner-Osborne, Hans

    2009-01-01

    Deorphanization of the large group of G protein-coupled receptors (GPCRs) for which an endogenous activating ligand has not yet been identified (orphan GPCRs) has become increasingly difficult. A specialized technique that has been successfully applied to deorphanize some of these GPCRs involves...... two-electrode voltage-clamp recordings of currents through ion channels, which are activated by GPCRs heterologously expressed in Xenopus oocytes. The ion channels that couple to GPCR activation in Xenopus oocytes can be endogenous calcium-activated chloride channels (CaCCs) or heterologously...... expressed G protein-coupled inwardly rectifying potassium channels (GIRKs). We will describe a general approach for expression of GPCRs in Xenopus oocytes and characterization of these using electrophysiological recordings. We will focus on the detection of GPCR activation by recordings of currents through...

  13. Oyster Electrophysiology: Electrocardiogram Signal Recognition and Interpretation

    Directory of Open Access Journals (Sweden)

    Frederico M. Batista

    2015-06-01

    Full Text Available After 100 years of published recording traces pertaining to the oyster electrocardiogram (ECG, we revisited the original experiments of Eiger (1913, using state-of-the-art electrophysiology recorders. Our aim was to confirm that a recordable ECG, similar to that of higher vertebrates, is present in the oyster heart. Portuguese oysters Crassostrea angulata, collected from the Guadiana estuary, Portugal, were used. The oysters were drilled through the right valve to reveal the pericardium. Gold and silver electrodes were placed through the hole and electrophysiological recordings were obtained. Stimulation of the oyster heart was performed in vivo and in vitro using a constant current power supply. Placement of electrodes around the heart revealed a trace that very closely matched the published ECG of Eiger (1913. However, we were unable to confirm that the recording was an ECG of the oyster heart. Moreover, measurements on isolated oyster hearts revealed a low conductivity (0.10 S m‒1. We did, however, record a depolarization signal from what we believe to be the visceral ganglia, and this preceded contractions of the oyster heart. Our findings indicate that so-called ECGs, previously recorded by [2] in Ostrea edulis, but also the “ECG” recorded by [4] in C. virginica from oyster hearts, are in fact an artifact arising from relative movement of the recording electrodes, giving rise to a baseline shift that mimics in some ways the P and QRS features of a typical ECG. Nevertheless, such recordings provide information pertaining to heart rate and are not without importance.

  14. GPU accelerated solver for nonlinear reaction-diffusion systems. Application to the electrophysiology problem

    Science.gov (United States)

    Mena, Andres; Ferrero, Jose M.; Rodriguez Matas, Jose F.

    2015-11-01

    Solving the electric activity of the heart possess a big challenge, not only because of the structural complexities inherent to the heart tissue, but also because of the complex electric behaviour of the cardiac cells. The multi-scale nature of the electrophysiology problem makes difficult its numerical solution, requiring temporal and spatial resolutions of 0.1 ms and 0.2 mm respectively for accurate simulations, leading to models with millions degrees of freedom that need to be solved for thousand time steps. Solution of this problem requires the use of algorithms with higher level of parallelism in multi-core platforms. In this regard the newer programmable graphic processing units (GPU) has become a valid alternative due to their tremendous computational horsepower. This paper presents results obtained with a novel electrophysiology simulation software entirely developed in Compute Unified Device Architecture (CUDA). The software implements fully explicit and semi-implicit solvers for the monodomain model, using operator splitting. Performance is compared with classical multi-core MPI based solvers operating on dedicated high-performance computer clusters. Results obtained with the GPU based solver show enormous potential for this technology with accelerations over 50 × for three-dimensional problems.

  15. Cardiovascular magnetic resonance guided electrophysiology studies

    OpenAIRE

    Lardo Albert C; Kolandaivelu Aravindan; Halperin Henry R

    2009-01-01

    Abstract Catheter ablation is a first line treatment for many cardiac arrhythmias and is generally performed under x-ray fluoroscopy guidance. However, current techniques for ablating complex arrhythmias such as atrial fibrillation and ventricular tachycardia are associated with suboptimal success rates and prolonged radiation exposure. Pre-procedure 3D CMR has improved understanding of the anatomic basis of complex arrhythmias and is being used for planning and guidance of ablation procedure...

  16. Cardiac perception and cardiac control. A review.

    Science.gov (United States)

    Carroll, D

    1977-12-01

    The evidence regarding specific cardiac perception and discrimination, and its relationship to voluntary cardiac control, is critically reviewed. Studies are considered in three sections, depending on the method used to assess cardiac perception: questionnaire assessment, discrimination procedures, and heartbeat tracking. The heartbeat tracking procedure would appear to suffer least from interpretative difficulties. Recommendations are made regarding the style of analysis used to assess heartbeat perception in such tracking tasks. PMID:348240

  17. Electrophysiological abnormalities associated with extensive myelinated retinal nerve fibers

    Directory of Open Access Journals (Sweden)

    Su Ann Tay

    2012-01-01

    Full Text Available An observational case report of electrophysiological abnormalities in a patient with anisomyopic amblyopia as a result of unilateral extensive myelinated retinal nerve fibers (MNFs is illustrated. The electrophysiological readings revealed an abnormal pattern electroretinogram (PERG but normal full-field electroretinogram readings in the affected eye. The visual-evoked potential was also undetectable in that eye. Our findings suggest that extensive MNFs can be associated with electrophysiological abnormalities, in particular the PERG, which can aid in diagnosing the cause of impaired vision when associated with amblyopia.

  18. Remodeling of energy metabolism and absence of electrophysiological changes in hearts of obese hyperleptinemic mice. New insights into the pleiotropic role of leptin

    Directory of Open Access Journals (Sweden)

    Rocío eGuzmán-Ruiz

    2013-11-01

    Full Text Available Dietary treatment with high-fat diets (HFD triggers diabetes and hyperleptinemia, concomitantly with a partial state of leptin resistance that affects hepatic and adipose tissue but not the heart. In this context, characterized by widespread steatosis, cardiac lipid content remains unchanged. As previously reported, HFD-evoked hyperleptinemia could be a pivotal element contributing to increase fatty acid (FA metabolism in the heart and to to prevent cardiac steatosis. This metabolic adaptation might theoretically reduce energy efficiency in cardiomyocytes and lead to cardiac electrophysiological remodeling. Therefore the aim of the current study has been to investigate the impact of long-term HFD on cardiac metabolism and electrophysiological properties of the principal ionic currents responsible of the action potential duration in mouse cardiomyocytes. Male C57BL/6J mice were fed a control (10% kcal from fat or HFD (45% kcal from fat during 32 weeks. Quantification of enzymatic activities regulating mitochondrial uptake of pyruvate and FA showed an increase of both carnitine-palmitoyltransferase and citrate synthase activities together with a decrease of lactate dehydrogenase and pyruvate dehydrogenase activities. Increased expression of uncoupling protein-3, Mn- and Cu/Zn-superoxide dismutases and catalase were also detected. Total glutathione/oxidized glutathione ratios were unaffected by HFD. These data suggest that HFD triggers adaptive mechanisms aimed at i facilitating FA catabolism, and ii preventing oxidative stress. All these changes did not affect the duration of action potentials in cardiomyocytes and only slightly modified electrocardiographic parameters.

  19. Role of TGF-β on cardiac structural and electrical remodeling

    Directory of Open Access Journals (Sweden)

    Roberto Ramos-Mondragón

    2008-12-01

    Full Text Available Roberto Ramos-Mondragón, Carlos A Galindo, Guillermo AvilaDepartamento de Bioquímica, Cinvestav-IPN, MéxicoAbstract: The type β transforming growth factors (TGF-βs are involved in a number of human diseases, including heart failure and myocardial arrhythmias. In fact, during the last 20 years numerous studies have demonstrated that TGF-β affects the architecture of the heart under both normal and pathological conditions. Moreover, TGF-β signaling is currently under investigation, with the aim of discovering potential therapeutic roles in human disease. In contrast, only few studies have investigated whether TGF-β affects electrophysiological properties of the heart. This fact is surprising since electrical remodeling represents an important substrate for cardiac disease. This review discusses the potential role of TGF-β on cardiac excitation-contraction (EC coupling, action potentials, and ion channels. We also discuss the effects of TGF-β on cardiac development and disease from structural and electrophysiological points of view.Keywords: transforming growth factor, ion channel, cardiac electrophysiology

  20. Intra-His bundle block: clinical, electrocardiographic, and electrophysiologic characteristics

    OpenAIRE

    Andréa Eduardo M.; Atié Jacob; Maciel Washington A.; Oliveira Jr Nilson A. de; Camanho Luiz Eduardo; Belo Luís Gustavo; Carvalho Hecio Affonso de; Siqueira Leonardo; Saad Eduardo; Venancio Ana Claudia

    2002-01-01

    OBJECTIVE: To assess the clinical, electrocardiographic, and electrophysiologic characteristics of patients (pt) with intra-His bundle block undergoing an electrophysiologic study (EPS). METHODS: We analyzed the characteristics of 16 pt with second-degree atrioventricular block and symptoms of syncope or dyspnea, or both, undergoing conventional EPS. RESULTS: Intra-His bundle block was documented in 16 pt during an EPS. In 15 (94%) pt, the atrioventricular block was recorded in sinus rhythm; ...

  1. Stimfit: quantifying electrophysiological data with Python

    Directory of Open Access Journals (Sweden)

    Segundo Jose Guzman

    2014-02-01

    Full Text Available Intracellular electrophysiological recordings provide crucial insights into elementary neuronal signals such as action potentials and synaptic currents. Analyzing and interpreting these signals is essential for a quantitative understanding of neuronal information processing, and requires both fast data visualization and ready access to complex analysis routines. To achieve this goal, we have developed Stimfit, a free software package for cellular neurophysiology with a Python scripting interface and a built-in Python shell. The program supports most standard file formats for cellular neurophysiology and other biomedical signals through the Biosig library. To quantify and interpret the activity of single neurons and communication between neurons, the program includes algorithms to characterize the kinetics of presynaptic action potentials and postsynaptic currents, estimate latencies between pre- and postsynaptic events, and detect spontaneously occurring events. We validate and benchmark these algorithms, give estimation errors, and provide sample use cases, showing that Stimfit represents an efficient, accessible and extensible way to accurately analyze and interpret neuronal signals.

  2. Autism--genetics, electrophysiology and clinical syndromes.

    Science.gov (United States)

    Pop-Jordanova, Nada; Plasevska-Karanfilska, Dijana

    2014-01-01

    Autism is a severe and the most heritable developmental disorder, whose pathogenesis is still largely unknown. The rising incidence of autism in the last decade has increased the scientific interest and research. More than a thousand papers concerned with information about the etiology of this "static disorder of the immature brain" can be found on Pub Med. The aim of this paper is to give a review of published genetic chromosomal anomalies associated with autistic spectrum disorders, as well as to discuss common syndromes associated with autistic traits. In addition, some of our own findings in genetics, as well as in quantitative electroencephalography and neurofeedback training in autistic children, will be presented and discussed. Generally, the subsequent analyses indicate that the causes of autism include fewer common single-gene mutations and chromosomal abnormalities, as well as multiple interacting genes of weak effect. Genome-wide linkage analysis has identified several susceptibility loci and positional and functional candidate genes which appear to represent possible risks of the autistic spectrum. Electrophysiological findings showed high delta/theta activity in frontal-central regions, while in 25% high beta activity was detected as a result of anxiety. Neurofeedback is a promising therapy for symptom mitigation.

  3. Electrophysiological study in neuromuscular junction disorders

    Directory of Open Access Journals (Sweden)

    Ajith Cherian

    2013-01-01

    Full Text Available This review is on ultrastructure and subcellular physiology at normal and abnormal neuromuscular junctions. The clinical and electrophysiological findings in myasthenia gravis, Lambert-Eaton myasthenic syndrome (LEMS, congenital myasthenic syndromes, and botulinum intoxication are discussed. Single fiber electromyography (SFEMG helps to explain the basis of testing neuromuscular junction function by repetitive nerve stimulation (RNS. SFEMG requires skill and patience and its availability is limited to a few centers. For RNS supramaximal stimulation is essential and so is display of the whole waveform of each muscle response at maximum amplitude. The amplitudes of the negative phase of the first and fourth responses are measured from baseline to negative peak, and the percent change of the fourth response compared with the first represents the decrement or increment. A decrement greater than 10% is accepted as abnormal and smooth progression of response amplitude train and reproducibility form the crux. In suspected LEMS the effect of fast rates of stimulation should be determined after RNS response to slow rates of stimulation. Caution is required to avoid misinterpretation of potentiation and pseudofacilitation.

  4. Closed-loop, open-source electrophysiology

    Directory of Open Access Journals (Sweden)

    John D Rolston

    2010-09-01

    Full Text Available Multiple extracellular microelectrodes (multi-electrode arrays, or MEAs effectively record rapidly varying neural signals, and can also be used for electrical stimulation. Multi-electrode recording can serve as artificial output (efferents from a neural system, while complex spatially and temporally targeted stimulation can serve as artificial input (afferents to the neuronal network. Multi-unit or local field potential recordings can not only be used to control real world artifacts, such as prostheses, computers or robots, but can also trigger or alter subsequent stimulation. Real-time feedback stimulation may serve to modulate or normalize aberrant neural activity, to induce plasticity, or to serve as artificial sensory input. Despite promising closed-loop applications, commercial electrophysiology systems do not yet take advantage of the bidirectional capabilities of multi-electrodes, especially for use in freely moving animals. We addressed this lack of tools for closing the loop with NeuroRighter, an open-source system including recording hardware, stimulation hardware, and control software with a graphical user interface. The integrated system is capable of multi-electrode recording and simultaneous patterned microstimulation triggered by recordings with minimal stimulation artifact. The potential applications of closed-loop systems as research tools and clinical treatments are broad; we provide one example where epileptic activity recorded by a multi-electrode probe is used to trigger targeted stimulation, via that probe, to freely moving rodents.

  5. Electrophysiology of pumpkin seeds: Memristors in vivo.

    Science.gov (United States)

    Volkov, Alexander G; Nyasani, Eunice K; Tuckett, Clayton; Greeman, Esther A; Markin, Vladislav S

    2016-01-01

    Leon Chua, the discoverer of a memristor, theoretically predicted that voltage gated ion channels can be memristors. We recently found memristors in different plants such as the Venus flytrap, Mimosa pudica, Aloe vera, apple fruits, and in potato tubers. There are no publications in literature about the existence of memristors in seeds. The goal of this work was to discover if pumpkin seeds might have memristors. We selected Cucurbita pepo L., cv. Cinderella, Cucurbita maxima L. cv Warty Goblin, and Cucurbita maxima L., cv. Jarrahdale seeds for this analysis. In these seeds, we found the presence of resistors with memory. The analysis was based on cyclic voltammetry where a memristor should manifest itself as a nonlinear two-terminal electrical element, which exhibits a pinched hysteresis loop on a current-voltage plane for any bipolar cyclic voltage input signal. Dry dormant pumpkin seeds have very high electrical resistance without memristive properties. The electrostimulation by bipolar sinusoidal or triangular periodic waves induces electrical responses in imbibed pumpkin seeds with fingerprints of memristors. Tetraethylammonium chloride, an inhibitor of voltage gated K(+) channels, transforms a memristor to a resistor in pumpkin seeds. NPPB (5-Nitro-2-(3-phenylpropylamino)benzoic acid) inhibits the memristive properties of imbibed pumpkin seeds. The discovery of memristors in pumpkin seeds creates a new direction in the understanding of electrophysiological phenomena in seeds. PMID:26926652

  6. Microsystems for cell-based electrophysiology

    Science.gov (United States)

    Yobas, Levent

    2013-08-01

    Among the electrophysiology techniques, the voltage clamp and its subsequent scaling to smaller mammalian cells, the so-called patch clamp, led to fundamental discoveries in the last century, revealing the ionic mechanisms and the role of single-ion channels in the generation and propagation of action potentials through excitable membranes (e.g. nerves and muscles). Since then, these techniques have gained a reputation as the gold standard of studying cellular ion channels owing to their high accuracy and rich information content via direct measurements under a controlled membrane potential. However, their delicate and skill-laden procedure has put a serious constrain on the throughput and their immediate utilization in the discovery of new cures targeting ion channels until researchers discovered ‘lab-on-a-chip’ as a viable platform for the automation of these techniques into a reliable high-throughput screening functional assay on ion channels. This review examines the innovative ‘lab-on-a-chip’ microtechnologies demonstrated towards this target over a period of slightly more than a decade. The technologies are categorically reviewed according to their considerations for design, fabrication, as well as microfluidic integration from a performance perspective with reference to their ability to secure G Ω seals (gigaseals) on cells, the norm broadly accepted among electrophysiologists for quality recordings that reflect ion-channel activity with high fidelity.

  7. Closed-loop, open-source electrophysiology.

    Science.gov (United States)

    Rolston, John D; Gross, Robert E; Potter, Steve M

    2010-01-01

    Multiple extracellular microelectrodes (multi-electrode arrays, or MEAs) effectively record rapidly varying neural signals, and can also be used for electrical stimulation. Multi-electrode recording can serve as artificial output (efferents) from a neural system, while complex spatially and temporally targeted stimulation can serve as artificial input (afferents) to the neuronal network. Multi-unit or local field potential (LFP) recordings can not only be used to control real world artifacts, such as prostheses, computers or robots, but can also trigger or alter subsequent stimulation. Real-time feedback stimulation may serve to modulate or normalize aberrant neural activity, to induce plasticity, or to serve as artificial sensory input. Despite promising closed-loop applications, commercial electrophysiology systems do not yet take advantage of the bidirectional capabilities of multi-electrodes, especially for use in freely moving animals. We addressed this lack of tools for closing the loop with NeuroRighter, an open-source system including recording hardware, stimulation hardware, and control software with a graphical user interface. The integrated system is capable of multi-electrode recording and simultaneous patterned microstimulation (triggered by recordings) with minimal stimulation artifact. The potential applications of closed-loop systems as research tools and clinical treatments are broad; we provide one example where epileptic activity recorded by a multi-electrode probe is used to trigger targeted stimulation, via that probe, to freely moving rodents. PMID:20859448

  8. Electrophysiological study in neuromuscular junction disorders.

    Science.gov (United States)

    Cherian, Ajith; Baheti, Neeraj N; Iype, Thomas

    2013-01-01

    This review is on ultrastructure and subcellular physiology at normal and abnormal neuromuscular junctions. The clinical and electrophysiological findings in myasthenia gravis, Lambert-Eaton myasthenic syndrome (LEMS), congenital myasthenic syndromes, and botulinum intoxication are discussed. Single fiber electromyography (SFEMG) helps to explain the basis of testing neuromuscular junction function by repetitive nerve stimulation (RNS). SFEMG requires skill and patience and its availability is limited to a few centers. For RNS supramaximal stimulation is essential and so is display of the whole waveform of each muscle response at maximum amplitude. The amplitudes of the negative phase of the first and fourth responses are measured from baseline to negative peak, and the percent change of the fourth response compared with the first represents the decrement or increment. A decrement greater than 10% is accepted as abnormal and smooth progression of response amplitude train and reproducibility form the crux. In suspected LEMS the effect of fast rates of stimulation should be determined after RNS response to slow rates of stimulation. Caution is required to avoid misinterpretation of potentiation and pseudofacilitation. PMID:23661960

  9. Whodunnit? Electrophysiological correlates of agency judgements.

    Directory of Open Access Journals (Sweden)

    Simone Kühn

    Full Text Available Sense of agency refers to the feeling that "I" am responsible for those external events that are directly produced by one's own voluntary actions. Recent theories distinguish between a non-conceptual "feeling" of agency linked to changes in the processing of self-generated sensory events, and a higher-order judgement of agency, which attributes sensory events to the self. In the current study we explore the neural correlates of the judgement of agency by means of electrophysiology. We measured event-related potentials to tones that were either perceived or not perceived as triggered by participants' voluntary actions and related these potentials to later judgements of agency over the tones. Replicating earlier findings on predictive sensory attenuation, we found that the N1 component was attenuated for congruent tones that corresponded to the learned action-effect mapping as opposed to incongruent tones that did not correspond to the previously acquired associations between actions and tones. The P3a component, but not the N1, directly reflected the judgement of agency: deflections in this component were greater for tones judged as self-generated than for tones judged as externally produced. The fact that the outcome of the later agency judgement was predictable based on the P3a component demonstrates that agency judgements incorporate early information processing components and are not purely reconstructive, post-hoc evaluations generated at time of judgement.

  10. Electrophysiological measurements of spectral sensitivities: a review

    Directory of Open Access Journals (Sweden)

    R.D. DeVoe

    1997-02-01

    Full Text Available Spectral sensitivities of visual systems are specified as the reciprocals of the intensities of light (quantum fluxes needed at each wavelength to elicit the same criterion amplitude of responses. This review primarily considers the methods that have been developed for electrophysiological determinations of criterion amplitudes of slow-wave responses from single retinal cells. Traditional flash methods can require tedious dark adaptations and may yield erroneous spectral sensitivity curves which are not seen in such modifications as ramp methods. Linear response methods involve interferometry, while constant response methods involve manual or automatic adjustments of continuous illumination to keep response amplitudes constant during spectral scans. In DC or AC computerized constant response methods, feedback to determine intensities at each wavelength is derived from the response amplitudes themselves. Although all but traditional flash methods have greater or lesser abilities to provide on-line determinations of spectral sensitivities, computerized constant response methods are the most satisfactory due to flexibility, speed and maintenance of a constant adaptation level

  11. Organic transistors for electrophysiology (Presentation Recording)

    Science.gov (United States)

    Rivnay, Jonathan

    2015-10-01

    Efficient local transduction of biological signals is of critical importance for mapping brain activity and diagnosing pathological conditions. Traditional devices used to record electrophysiological signals are passive electrodes that require (pre)amplification with downstream electronics. Organic electrochemical transistors (OECTs) that utilize conducting polymer films as the channel have shown considerable promise as amplifying transducers due to their stability in aqueous conditions and high transconductance (>3 mS). The materials properties and physics of such transistors, however, remains largely unexplored thus limiting their potential. Here we show that the uptake of ionic charge from an electrolyte into a poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) OECT channel leads to a dependence of the effective capacitance on the entire volume of the film. Subsequently, device transconductance and time response vary with channel thickness, a defining characteristic that differentiates OECTs from field effect transistors, and provides a new degree of freedom for device engineering. Using this understanding we tailor OECTs for a variety of low (1-100 Hz) and high (1-10 kHz) frequency applications, including human electroencephalography, where high transconductance devices impart richer signal content without the need for additional amplification circuitry. We also show that the materials figure of merit OECTs is the product of hole mobility and volumetric capacitance of the channel, leading to design rules for novel high performance materials.

  12. Microsystems for cell-based electrophysiology

    International Nuclear Information System (INIS)

    Among the electrophysiology techniques, the voltage clamp and its subsequent scaling to smaller mammalian cells, the so-called patch clamp, led to fundamental discoveries in the last century, revealing the ionic mechanisms and the role of single-ion channels in the generation and propagation of action potentials through excitable membranes (e.g. nerves and muscles). Since then, these techniques have gained a reputation as the gold standard of studying cellular ion channels owing to their high accuracy and rich information content via direct measurements under a controlled membrane potential. However, their delicate and skill-laden procedure has put a serious constrain on the throughput and their immediate utilization in the discovery of new cures targeting ion channels until researchers discovered ‘lab-on-a-chip’ as a viable platform for the automation of these techniques into a reliable high-throughput screening functional assay on ion channels. This review examines the innovative ‘lab-on-a-chip’ microtechnologies demonstrated towards this target over a period of slightly more than a decade. The technologies are categorically reviewed according to their considerations for design, fabrication, as well as microfluidic integration from a performance perspective with reference to their ability to secure G Ω seals (gigaseals) on cells, the norm broadly accepted among electrophysiologists for quality recordings that reflect ion-channel activity with high fidelity. (topical review)

  13. [Electrophysiological bases of semantic processing of objects].

    Science.gov (United States)

    Kahlaoui, Karima; Baccino, Thierry; Joanette, Yves; Magnié, Marie-Noële

    2007-02-01

    How pictures and words are stored and processed in the human brain constitute a long-standing question in cognitive psychology. Behavioral studies have yielded a large amount of data addressing this issue. Generally speaking, these data show that there are some interactions between the semantic processing of pictures and words. However, behavioral methods can provide only limited insight into certain findings. Fortunately, Event-Related Potential (ERP) provides on-line cues about the temporal nature of cognitive processes and contributes to the exploration of their neural substrates. ERPs have been used in order to better understand semantic processing of words and pictures. The main objective of this article is to offer an overview of the electrophysiologic bases of semantic processing of words and pictures. Studies presented in this article showed that the processing of words is associated with an N 400 component, whereas pictures elicited both N 300 and N 400 components. Topographical analysis of the N 400 distribution over the scalp is compatible with the idea that both image-mediated concrete words and pictures access an amodal semantic system. However, given the distinctive N 300 patterns, observed only during picture processing, it appears that picture and word processing rely upon distinct neuronal networks, even if they end up activating more or less similar semantic representations. PMID:17291430

  14. Cardiac sodium channelopathies

    NARCIS (Netherlands)

    A.S. Amin; A. Asghari-Roodsari; H.L. Tan

    2010-01-01

    Cardiac sodium channel are protein complexes that are expressed in the sarcolemma of cardiomyocytes to carry a large inward depolarizing current (I-Na) during phase 0 of the cardiac action potential. The importance of I-Na for normal cardiac electrical activity is reflected by the high incidence of

  15. Diffuse infiltrative cardiac tuberculosis

    International Nuclear Information System (INIS)

    We present the cardiac magnetic resonance images of an unusual form of cardiac tuberculosis. Nodular masses in a sheet-like distribution were seen to infiltrate the outer myocardium and pericardium along most of the cardiac chambers. The lesions showed significant resolution on antitubercular therapy

  16. Assessment of the cellular and electrophysiological response of cardiomyocytes to radiation

    Science.gov (United States)

    Helm, Alexander; Ritter, Sylvia; Durante, Marco; Friess, Johannes; Thielemann, Christiane; Mr; Frank, Simon

    Cardiac disease is considered as a late effect resulting from an exposure during long-term space missions. Yet, the underlying mechanisms and the impact of radiation quality and dose are not well understood. To address this topic, we used cardiomyocytes derived from mouse embryonic stem cells (mESC) as a model system. This model has already been successfully used for cardiotoxicity screening of new drugs. Both, the cellular and electrophysiological response to X-ray irradiation were examined. Cellular endpoints such as the induction of micronuclei, apoptosis, number of binucleated cells and expression of connexin43 (Cx 43) were analyzed by standard techniques. For electrophysiological studies a microelectrode array (MEA) was used allowing non-invasive recordings of electrical signals such as signal amplitude and shape, beat rate and conduction velocity. Data analysis was performed using the MATLAB based software DrCell. As a first approach, cardiomyocytes were generated by differentiation of mESC via the formation of embryoid bodies. However, the system proved to be unsuitable due to large intra- and inter-sample variations. In consecutive experiments we used commercially available Cor.At cells, i.e. a pure culture of mESC derived cardiomyocytes. For the analysis of cellular and electrophysiological endpoints Cor.At cells were seeded onto chamber slides or MEA chips, respectively. Irradiation with 0.5 and 2 Gy X-rays (250 kV, 16 mA) was performed two days after seeding. At that time cardiomyocytes are electrically coupled through gap junctions and form a spontaneously beating network. Samples were examined up to four days after exposure. Analysis of the electrophysiological data revealed only minor differences between controls and X-irradiated samples indicating the functionality of cardiomyocytes is not within the dose range examined. Currently, further experiments are performed to statistically verify this finding. Additionally, the expression of Cx 43, a major

  17. Cardiac tumours in children

    Directory of Open Access Journals (Sweden)

    Parsons Jonathan M

    2007-03-01

    Full Text Available Abstract Cardiac tumours are benign or malignant neoplasms arising primarily in the inner lining, muscle layer, or the surrounding pericardium of the heart. They can be primary or metastatic. Primary cardiac tumours are rare in paediatric practice with a prevalence of 0.0017 to 0.28 in autopsy series. In contrast, the incidence of cardiac tumours during foetal life has been reported to be approximately 0.14%. The vast majority of primary cardiac tumours in children are benign, whilst approximately 10% are malignant. Secondary malignant tumours are 10–20 times more prevalent than primary malignant tumours. Rhabdomyoma is the most common cardiac tumour during foetal life and childhood. It accounts for more than 60% of all primary cardiac tumours. The frequency and type of cardiac tumours in adults differ from those in children with 75% being benign and 25% being malignant. Myxomas are the most common primary tumours in adults constituting 40% of benign tumours. Sarcomas make up 75% of malignant cardiac masses. Echocardiography, Computing Tomography (CT and Magnetic Resonance Imaging (MRI of the heart are the main non-invasive diagnostic tools. Cardiac catheterisation is seldom necessary. Tumour biopsy with histological assessment remains the gold standard for confirmation of the diagnosis. Surgical resection of primary cardiac tumours should be considered to relieve symptoms and mechanical obstruction to blood flow. The outcome of surgical resection in symptomatic, non-myxomatous benign cardiac tumours is favourable. Patients with primary cardiac malignancies may benefit from palliative surgery but this approach should not be recommended for patients with metastatic cardiac tumours. Surgery, chemotherapy and radiotherapy may prolong survival. The prognosis for malignant primary cardiac tumours is generally extremely poor.

  18. Cardiac electrophysiological effects of selective adrenoceptor stimulation and their possible roles in arrhythmias.

    Science.gov (United States)

    Vaughan Williams, E M

    1985-01-01

    The selective alpha 1- and alpha 2-adrenoceptor agonists St 587 and BHT 933, respectively, and the antagonists prazosin (alpha 1) and WY 25309 (alpha 2) have been used in combination with the selective beta 2-adrenoceptor agonist pirbuterol, and the antagonists atenolol (beta 1) and ICI 118551 (beta 2), to analyse the effects of individual types of adrenoceptor stimulation in various parts of the rabbit heart. In the sinus node, beta 1-, but not beta 2-adrenoceptor stimulation increased the fast phase of depolarisation. Both beta 1- and beta 2-adrenoceptor stimulation increased the slope of the slow diastolic depolarisation, accelerated repolarisation, and increased maximum diastolic potential. Beta 1- and beta 2-adrenoceptor stimulation also accelerated repolarisation in Purkinje cells and papillary muscle. After blockade of both beta 1- and beta 2-adrenoceptors, alpha 1-adrenoceptor stimulation caused bradycardia, owing exclusively to delayed repolarisation. Alpha 2-adrenoceptor stimulation had no effect. Beta 1-, but not beta 2-adrenoceptor stimulation augmented peak contractions three- to fivefold, and reduced the time-to-peak tension. In contrast, alpha 1-adrenoceptor stimulation only moderately (up to 47%) increased peak tension, but increased time-to-peak and duration of contractions. The results would be consistent with beta 1-adrenoceptor stimulation increasing inward calcium current, and with stimulation of alpha 1-adrenoceptors delaying the decline of [Ca]i rather than increasing its magnitude. Both beta 1- and beta 2-stimulation increased repolarising current, but alpha 1-stimulation decreased it.

  19. Materials for Multifunctional Balloon Catheters With Capabilities in Cardiac Electrophysiological Mapping and Ablation Therapy

    OpenAIRE

    Kim, Dae-Hyeong; Lu, Nanshu; Ghaffari, Roozbeh; Kim, Yun-Soung; Lee, Stephen P.; Xu, Lizhi; Wu, Jian; Kim, Rak-Hwan; Song, Jizhou; Liu, Zhuangjian; Viventi, Jonathan; de Graff, Bassel; Elolampi, Brian; Mansour, Moussa; Slepian, Marvin J.

    2011-01-01

    Development of advanced surgical tools for minimally invasive procedures represents an activity of central importance to improvements in human health. A key materials challenge is in the realization of bio-compatible interfaces between the classes of semiconductor and sensor technologies that might be most useful in this context and the soft, curvilinear surfaces of the body. This paper describes a solution based on biocompatible materials and devices that integrate directly with the thin ela...

  20. A Conformal, Bio-interfaced Class of Silicon Electronics for Mapping Cardiac Electrophysiology

    OpenAIRE

    Viventi, Jonathan; Kim, Dae-Hyeong; Moss, Joshua D.; Kim, Yun-Soung; Blanco, Justin A; Annetta, Nicholas; Hicks, Andrew; Xiao, Jianliang; Huang, Younggang; David J. Callans; Rogers, John A.; Litt, Brian

    2010-01-01

    The sophistication and resolution of current implantable medical devices are limited by the need connect each sensor separately to data acquisition systems. The ability of these devices to sample and modulate tissues is further limited by the rigid, planar nature of the electronics and the electrode-tissue interface. Here, we report the development of a class of mechanically flexible silicon electronics for measuring signals in an intimate, conformal integrated mode on the dynamic, three dime...

  1. Ionic diffusion in voltage-clamped isolated cardiac myocytes. Implications for Na,K-pump studies.

    OpenAIRE

    Mogul, D J; Singer, D H; ten Eick, R E

    1989-01-01

    The whole-cell voltage-clamp technique employing electrolyte-filled micro-pipette suction electrodes is widely used to investigate questions requiring an electrophysiological approach. With this technique, the ionic composition of the cytosol is assumed to be strongly influenced (as result of diffusion) by the ionic composition of the solution contained in the electrode. If this assumption is valid for isolated cardiac myocytes, the technique would be particularly powerful for studying the de...

  2. Stimulating endogenous cardiac regeneration

    Directory of Open Access Journals (Sweden)

    Amanda eFinan

    2015-09-01

    Full Text Available The healthy adult heart has a low turnover of cardiac myocytes. The renewal capacity, however, is augmented after cardiac injury. Participants in cardiac regeneration include cardiac myocytes themselves, cardiac progenitor cells, and peripheral stem cells, particularly from the bone marrow compartment. Cardiac progenitor cells and bone marrow stem cells are augmented after cardiac injury, migrate to the myocardium, and support regeneration. Depletion studies of these populations have demonstrated their necessary role in cardiac repair. However, the potential of these cells to completely regenerate the heart is limited. Efforts are now being focused on ways to augment these natural pathways to improve cardiac healing, primarily after ischemic injury but in other cardiac pathologies as well. Cell and gene therapy or pharmacological interventions are proposed mechanisms. Cell therapy has demonstrated modest results and has passed into clinical trials. However, the beneficial effects of cell therapy have primarily been their ability to produce paracrine effects on the cardiac tissue and recruit endogenous stem cell populations as opposed to direct cardiac regeneration. Gene therapy efforts have focused on prolonging or reactivating natural signaling pathways. Positive results have been demonstrated to activate the endogenous stem cell populations and are currently being tested in clinical trials. A potential new avenue may be to refine pharmacological treatments that are currently in place in the clinic. Evidence is mounting that drugs such as statins or beta blockers may alter endogenous stem cell activity. Understanding the effects of these drugs on stem cell repair while keeping in mind their primary function may strike a balance in myocardial healing. To maximize endogenous cardiac regeneration,a combination of these approaches couldameliorate the overall repair process to incorporate the participation ofmultiple cell players.

  3. Reentrant Supraventricular Tachycardia in a Pediatric Trauma Patient Masquerading as a Cardiac Contusion

    Directory of Open Access Journals (Sweden)

    Bradbum, Christopher

    2005-01-01

    Full Text Available Establishing the etiology of tachycardia in a trauma patient is often difficult. Pediatric trauma patients present an even tougher challenge. Cardiac contusion should be suspected when other more common traumatic injuries that produce hypoxia and blood loss are excluded. The diagnosis of cardiac contusion is notoriously difficult to make largely due to the controversy over the definition of the disease, and the lack of a true gold standard confirmatory test. Atrioventricular nodal reentrant tachycardia (AVNRT is a common form of supraventricular tachycardia (SVT that can also present a diagnostic challenge to emergency physicians. While electrophysiologic studies are the gold standard for confirming the diagnosis, there are certain aspects of the history, electrocardiogram (ECG, and responses to cardiac maneuvers that strongly suggest the diagnosis. We present the case of a pediatric trauma patient that presented with new onset AVNRT masquerading as cardiac contusion.

  4. Electrocardiographic Patch Devices and Contemporary Wireless Cardiac Monitoring

    Directory of Open Access Journals (Sweden)

    Erik eFung

    2015-05-01

    Full Text Available Cardiac electrophysiologic derangements often coexist with disorders of the circulatory system. Capturing and diagnosing arrhythmias and conduction system disease may lead to a change in diagnosis, clinical management and patient outcomes. Standard 12-lead electrocardiogram (ECG, Holter monitors and event recorders have served as useful diagnostic tools over the last few decades. However, their shortcomings are only recently being addressed by emerging technologies. With advances in device miniaturization and wireless technologies, and changing consumer expectations, wearable ‘on-body’ ECG patch devices have evolved to meet contemporary needs. These devices are unobtrusive and easy to use, leading to increased device wear time and diagnostic yield. While becoming the standard for detecting arrhythmias and conduction system disorders in the outpatient setting where continuous ECG monitoring in the short to medium term (days to weeks is indicated, these cardiac devices and related digital mobile health technologies are reshaping the clinician-patient interface with important implications for future healthcare delivery.

  5. Mechanism of relation among heart meridian, referred cardiac pain and heart

    Institute of Scientific and Technical Information of China (English)

    RONG; Peijing(荣培晶); ZHU; Bing(朱兵)

    2002-01-01

    It has been demonstrated that an important clinical phenomenon often associated with visceral diseases is the referred pain to somatic structures, especially to the body areaof homo-segmental innervation. It is interesting that the somatic foci of cardiac referred pain wereoften and mainly distributed along the heart meridian (HM), whereas the acupoints of HM havebeen applied to treat cardiac disease since ancient times. The purpose of this study was to inves-tigate the neural relationship between the cardiac referred pain and the heart meridian.Fluorescent triple-labeling was injected into the pericardium, some acupoints of HM and lung me-ridian (LM, for control). The responses of the left cardiac sympathetic nerve and of the EMG in left HM and LM were electrophysiologically studied, when the electrical stimuli were applied to the acupoints of left HM and to the left cardiac sympathetic nerve. More double-labeled neurons in HM-heart, not in LM-heart, were observed in the ipsilateral dorsal root ganglia of the spinal segments C8-T3. Electric stimulation of the acupoints of left HM was able to elicit more responses of left cardiac sympathetic nerve than that of the LM-acupoints. Electric stimulation of the left cardiac sympathetic nerve resulted in stronger activities of EMG-response in the acupoints of left HM than in LM-acupoints. We conclude that double-labeling study has provided direct evidence for the existence of dichotomizing afferent fibers that supply both the pericardium and HM. Electrophysiological results show that HM is more closely related functionally to heart. These findings provide a possible morphological and physiological explanation for the referred cardiac pain and HM-heart interrelation.

  6. Marketing cardiac CT programs.

    Science.gov (United States)

    Scott, Jason

    2010-01-01

    There are two components of cardiac CT discussed in this article: coronary artery calcium scoring (CACS) and coronary computed tomography angiography (CCTA).The distinctive advantages of each CT examination are outlined. In order to ensure a successful cardiac CT program, it is imperative that imaging facilities market their cardiac CT practices effectively in order to gain a competitive advantage in this valuable market share. If patients receive quality care by competent individuals, they are more likely to recommend the facility's cardiac CT program. Satisfied patients will also be more willing to come back for any further testing.

  7. Electrical storm: A clinical and electrophysiological overview

    Institute of Scientific and Technical Information of China (English)

    Sergio; Conti; Salvatore; Pala; Viviana; Biagioli; Giuseppe; Del; Giorno; Martina; Zucchetti; Eleonora; Russo; Vittoria; Marino; Antonio; Dello; Russo; Michela; Casella; Francesca; Pizzamiglio; Valentina; Catto; Claudio; Tondo; Corrado; Carbucicchio

    2015-01-01

    Electrical storm(ES) is a clinical condition characterized by three or more ventricular arrhythmia episodes leading to appropriate implantable cardioverterdefibrillator(ICD) therapies in a 24 h period. Mostly, arrhythmias responsible of ES are multiple morphologies of monomorphic ventricular tachycardia(VT), but polymorphic VT and ventricular fibrillation can also result in ES. Clinical presentation is very dramatic in most cases, strictly related to the cardiac disease that may worsen electrical and hemodynamic decompensation. Therefore ES management is challenging in the majority of cases and a high mortality is the rule both in the acute and in the long-term phases. Different underlying cardiomyopathies provide significant clues into the mechanism of ES, which can arise in the setting of structural arrhythmogenic cardiomyopathies or rarely in patients with inherited arrhythmic syndrome, impacting on pharmacological treatment, on ICD programming, and on the opportunity to apply strategies of catheter ablation. This latter has become a pivotal form of treatment due to its high efficacy in modifying the arrhythmogenic substrate and in achieving rhythm stability, aiming at reducing recurrences of ventricular arrhythmia and at improving overall survival. In this review, the most relevant epidemiological and clinical aspects of ES, with regard to the acute and long-term follow-up implications, were evaluated, focusing on these novel therapeutic strategies of treatment.

  8. Use of human stem cell derived cardiomyocytes to examine sunitinib mediated cardiotoxicity and electrophysiological alterations

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, J.D., E-mail: jennifer.cohen@roche.com [Early and Investigative Safety, Nonclinical Safety, Hoffmann-La Roche, 340 Kingsland Street, Nutley, NJ 07110 (United States); Babiarz, J.E., E-mail: joshua.babiarz@roche.com [Early and Investigative Safety, Nonclinical Safety, Hoffmann-La Roche, 340 Kingsland Street, Nutley, NJ 07110 (United States); Abrams, R.M., E-mail: rory.abrams@roche.com [Early and Investigative Safety, Nonclinical Safety, Hoffmann-La Roche, 340 Kingsland Street, Nutley, NJ 07110 (United States); Guo, L., E-mail: liang.guo@roche.com [Early and Investigative Safety, Nonclinical Safety, Hoffmann-La Roche, 340 Kingsland Street, Nutley, NJ 07110 (United States); Kameoka, S., E-mail: sei.kameoka@roche.com [Early and Investigative Safety, Nonclinical Safety, Hoffmann-La Roche, 340 Kingsland Street, Nutley, NJ 07110 (United States); Chiao, E., E-mail: eric.chiao@roche.com [Early and Investigative Safety, Nonclinical Safety, Hoffmann-La Roche, 340 Kingsland Street, Nutley, NJ 07110 (United States); Taunton, J., E-mail: taunton@cmp.ucsf.edu [Howard Hughes Medical Institute, Cellular and Molecular Pharmacology, University California San Francisco, San Francisco, CA 94158 (United States); Kolaja, K.L., E-mail: kyle.kolaja@roche.com [Early and Investigative Safety, Nonclinical Safety, Hoffmann-La Roche, 340 Kingsland Street, Nutley, NJ 07110 (United States)

    2011-11-15

    Sunitinib, an oral tyrosine kinase inhibitor approved to treat advanced renal cell carcinoma and gastrointestinal stroma tumor, is associated with clinical cardiac toxicity. Although the precise mechanism of sunitinib cardiotoxicity is not known, both the key metabolic energy regulator, AMP-activated protein kinase (AMPK), and ribosomal S 6 kinase (RSK) have been hypothesized as causative, albeit based on rodent models. To study the mechanism of sunitinib-mediated cardiotoxicity in a human model, induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) having electrophysiological and contractile properties of native cardiac tissue were investigated. Sunitinib was cardiotoxic in a dose-dependent manner with an IC{sub 50} in the low micromolar range, observed by a loss of cellular ATP, an increase in oxidized glutathione, and induction of apoptosis in iPSC-CMs. Pretreatment of iPSC-CMs with AMPK activators AICAR or metformin, increased the phosphorylation of pAMPK-T172 and pACC-S79, but only marginally attenuated sunitinib mediated cell death. Furthermore, additional inhibitors of AMPK were not directly cytotoxic to iPSC-CMs up to 250 {mu}M concentrations. Inhibition of RSK with a highly specific, irreversible, small molecule inhibitor (RSK-FMK-MEA) did not induce cytotoxicity in iPSC-CMs below 250 {mu}M. Extensive electrophysiological analysis of sunitinib and RSK-FMK-MEA mediated conduction effects were performed. Taken together, these findings suggest that inhibition of AMPK and RSK are not a major component of sunitinib-induced cardiotoxicity. Although the exact mechanism of cardiotoxicity of sunitinib is not known, it is likely due to inhibition of multiple kinases simultaneously. These data highlight the utility of human iPSC-CMs in investigating the potential molecular mechanisms underlying drug-induced cardiotoxicity. -- Highlights: Black-Right-Pointing-Pointer Cytoxic effect of sunitinib on human stem cell derived cardiomyocytes Black

  9. Predicting changes in cardiac myocyte contractility during early drug discovery with in vitro assays

    Energy Technology Data Exchange (ETDEWEB)

    Morton, M.J., E-mail: michael.morton@astrazeneca.com [Discovery Sciences, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom); Armstrong, D.; Abi Gerges, N. [Drug Safety and Metabolism, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom); Bridgland-Taylor, M. [Discovery Sciences, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom); Pollard, C.E.; Bowes, J.; Valentin, J.-P. [Drug Safety and Metabolism, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom)

    2014-09-01

    Cardiovascular-related adverse drug effects are a major concern for the pharmaceutical industry. Activity of an investigational drug at the L-type calcium channel could manifest in a number of ways, including changes in cardiac contractility. The aim of this study was to define which of the two assay technologies – radioligand-binding or automated electrophysiology – was most predictive of contractility effects in an in vitro myocyte contractility assay. The activity of reference and proprietary compounds at the L-type calcium channel was measured by radioligand-binding assays, conventional patch-clamp, automated electrophysiology, and by measurement of contractility in canine isolated cardiac myocytes. Activity in the radioligand-binding assay at the L-type Ca channel phenylalkylamine binding site was most predictive of an inotropic effect in the canine cardiac myocyte assay. The sensitivity was 73%, specificity 83% and predictivity 78%. The radioligand-binding assay may be run at a single test concentration and potency estimated. The least predictive assay was automated electrophysiology which showed a significant bias when compared with other assay formats. Given the importance of the L-type calcium channel, not just in cardiac function, but also in other organ systems, a screening strategy emerges whereby single concentration ligand-binding can be performed early in the discovery process with sufficient predictivity, throughput and turnaround time to influence chemical design and address a significant safety-related liability, at relatively low cost. - Highlights: • The L-type calcium channel is a significant safety liability during drug discovery. • Radioligand-binding to the L-type calcium channel can be measured in vitro. • The assay can be run at a single test concentration as part of a screening cascade. • This measurement is highly predictive of changes in cardiac myocyte contractility.

  10. Predicting changes in cardiac myocyte contractility during early drug discovery with in vitro assays

    International Nuclear Information System (INIS)

    Cardiovascular-related adverse drug effects are a major concern for the pharmaceutical industry. Activity of an investigational drug at the L-type calcium channel could manifest in a number of ways, including changes in cardiac contractility. The aim of this study was to define which of the two assay technologies – radioligand-binding or automated electrophysiology – was most predictive of contractility effects in an in vitro myocyte contractility assay. The activity of reference and proprietary compounds at the L-type calcium channel was measured by radioligand-binding assays, conventional patch-clamp, automated electrophysiology, and by measurement of contractility in canine isolated cardiac myocytes. Activity in the radioligand-binding assay at the L-type Ca channel phenylalkylamine binding site was most predictive of an inotropic effect in the canine cardiac myocyte assay. The sensitivity was 73%, specificity 83% and predictivity 78%. The radioligand-binding assay may be run at a single test concentration and potency estimated. The least predictive assay was automated electrophysiology which showed a significant bias when compared with other assay formats. Given the importance of the L-type calcium channel, not just in cardiac function, but also in other organ systems, a screening strategy emerges whereby single concentration ligand-binding can be performed early in the discovery process with sufficient predictivity, throughput and turnaround time to influence chemical design and address a significant safety-related liability, at relatively low cost. - Highlights: • The L-type calcium channel is a significant safety liability during drug discovery. • Radioligand-binding to the L-type calcium channel can be measured in vitro. • The assay can be run at a single test concentration as part of a screening cascade. • This measurement is highly predictive of changes in cardiac myocyte contractility

  11. Biomaterials for cardiac regeneration

    CERN Document Server

    Ruel, Marc

    2015-01-01

    This book offers readers a comprehensive biomaterials-based approach to achieving clinically successful, functionally integrated vasculogenesis and myogenesis in the heart. Coverage is multidisciplinary, including the role of extracellular matrices in cardiac development, whole-heart tissue engineering, imaging the mechanisms and effects of biomaterial-based cardiac regeneration, and autologous bioengineered heart valves. Bringing current knowledge together into a single volume, this book provides a compendium to students and new researchers in the field and constitutes a platform to allow for future developments and collaborative approaches in biomaterials-based regenerative medicine, even beyond cardiac applications. This book also: Provides a valuable overview of the engineering of biomaterials for cardiac regeneration, including coverage of combined biomaterials and stem cells, as well as extracellular matrices Presents readers with multidisciplinary coverage of biomaterials for cardiac repair, including ...

  12. PERIPHERAL NEUROPATHY ELECTROPHYSIOLOGICAL SCREENING IN CHILDREN WITH CELIAC DISEASE

    Directory of Open Access Journals (Sweden)

    Şedat IŞIKAY

    2015-06-01

    Full Text Available Background The involvement of the peripheral nervous system in children with celiac disease is particularly rare. Objective The aim of this study was to assess the need for neurophysiological testing in celiac disease patients without neurological symptoms in order to detect early subclinical neuropathy and its possible correlations with clinical and demographic characteristics. Methods Two hundred and twenty consecutive children with celiac disease were screened for neurological symptoms and signs, and those without symptoms or signs were included. Also, patients with comorbidities associated with peripheral neuropathy or a history of neurological disease were excluded. The remaining 167 asymptomatic patients as well as 100 control cases were tested electro-physiologically for peripheral nervous system diseases. Motor nerve conduction studies, including F-waves, were performed for the median, ulnar, peroneal, and tibial nerves, and sensory nerve conduction studies were performed for the median, ulnar, and sural nerves with H reflex of the soleus muscle unilaterally. All studies were carried out using surface recording electrodes. Normative values established in our laboratory were used. Results Evidence for subclinical neuropathy was not determined with electrophysiological studies in any of the participants. Conclusion In this highly selective celiac disease group without any signs, symptoms as well as the predisposing factors for polyneuropathy, we did not determine any cases with neuropathy. With these results we can conclude that in asymptomatic cases with celiac disease electrophysiological studies are not necessary. However, larger studies with the electrophysiological studies performed at different stages of disease at follow-ups are warranted.

  13. Electrophysiological Studies in Patients with Pulmonary Hypertension: A Retrospective Investigation

    Directory of Open Access Journals (Sweden)

    Dirk Bandorski

    2014-01-01

    Full Text Available Few studies have investigated patients with pulmonary hypertension and arrhythmias. Data on electrophysiological studies in these patients are rare. In a retrospective dual-centre design, we analysed data from patients with indications for electrophysiological study. Fifty-five patients with pulmonary hypertension were included (Dana Point Classification: group 1: 14, group 2: 23, group 3: 4, group 4: 8, group 5: 2, and 4 patients with exercised-induced pulmonary hypertension. Clinical data, 6-minute walk distance, laboratory values, and echocardiography were collected/performed. Nonsustained ventricular tachycardia was the most frequent indication (n=15 for an electrophysiological study, followed by atrial flutter (n=14. In summary 36 ablations were performed and 25 of them were successful (atrial flutter 12 of 14 and atrioventricular nodal reentrant tachycardia 4 of 4. Fluoroscopy time was 16 ± 14.4 minutes. Electrophysiological studies in patients with pulmonary hypertension are feasible and safe. Ablation procedures are as effective in these patients as in non-PAH patients with atrial flutter and atrioventricular nodal reentrant tachycardia and should be performed likewise. The prognostic relevance of ventricular stimulations and inducible ventricular tachycardias in these patients is still unclear and requires further investigation.

  14. The Electrophysiological Correlates of Scientific Innovation Induced by Heuristic Information

    Science.gov (United States)

    Luo, Junlong; Du, Xiumin; Tang, Xiaochen; Zhang, Entao; Li, Haijiang; Zhang, Qinglin

    2013-01-01

    In this study, novel and old scientific innovations (NSI and OSI) were selected as materials to explore the electrophysiological correlates of scientific innovation induced by heuristic information. Using event-related brain potentials (ERPs) to do so, college students solved NSI problems (for which they did not know the answers) and OSI problems…

  15. Error and reinforcement processing in ADHD : An electrophysiological study

    NARCIS (Netherlands)

    Groen, Yvonne

    2011-01-01

    Introduction and Objective(s) Current explanatory models of ADHD suggest abnormal reinforcement sensitivity, but the exact nature of this deficit is unclear. In this study we investigate electrophysiological reactions to positive/negative reinforcement as well as correct/error responses to gain more

  16. Hypoxic neuropathy versus diabetic neuropathy : an electrophysiological study in rats

    NARCIS (Netherlands)

    Gispen, W.H.; Hendriksen, P.H.; Oey, P.L.; Wieneke, G.H.; Huffelen, A.C. van

    1992-01-01

    In the experimental rat model of diabetes a slowing of nerve conduction velocity and a resistance to ischemic conduction failure have been found as an indication of polyneuropathy. The same electrophysiological abnormalities have been demonstrated in a model in which healthy rats are kept under hypo

  17. Dynamics of intrinsic electrophysiological properties in spinal cord neurones

    DEFF Research Database (Denmark)

    Russo, R E; Hounsgaard, J

    1999-01-01

    The spinal cord is engaged in a wide variety of functions including generation of motor acts, coding of sensory information and autonomic control. The intrinsic electrophysiological properties of spinal neurones represent a fundamental building block of the spinal circuits executing these tasks...

  18. Function and modulation of bacterial porins: insights from electrophysiology.

    Science.gov (United States)

    Delcour, A H

    1997-06-15

    Electrophysiological techniques provide a wealth of information regarding the molecular mechanisms that underlie the function and modulation of ion channels. They have revealed that bacterial porins do not behave as static, permanently open pores but display a much more complex and dynamic behavior than anticipated from non-electrophysiological studies. The channels switch between short-lived open and closed conformations (gating activity), and can also remain in an inactivated, non-ion conducting state for prolonged periods of time. Thus the role of porins is not limited to that of a molecular filter, but is extended to the control of outer membrane permeability through the regulation of their activity. Electrophysiological studies have indeed demonstrated that both gating and inactivation are modulated by a variety of physical and chemical parameters and are highly cooperative phenomena, often involving numerous channels working in concert. Cooperativity acts as an amplification mechanism that grants a large population of porins, such as found in the outer membrane, with sensitivity to modulation by external or internal factors. By conferring permeability properties to the outer membrane, porins play a crucial role in the bacterium's antibiotic susceptibility and survival in various environmental conditions. The detailed information that electrophysiology only can provide on porin function and modulation promises to yield a more accurate description of how porin properties can be used by cells to adapt to a changing environment, and to offer mechanisms that might optimize the drug sensitivity of the microorganism. PMID:9228742

  19. Scalable Electrophysiological Investigation of iPS Cell-Derived Cardiomyocytes Obtained by a Lentiviral Purification Strategy

    Directory of Open Access Journals (Sweden)

    Stephanie Friedrichs

    2015-01-01

    Full Text Available Disease-specific induced pluripotent stem (iPS cells can be generated from patients and differentiated into functional cardiomyocytes for characterization of the disease and for drug screening. In order to obtain pure cardiomyocytes for automated electrophysiological investigation, we here report a novel non-clonal purification strategy by using lentiviral gene transfer of a puromycin resistance gene under the control of a cardiac-specific promoter. We have applied this method to our previous reported wild-type and long QT syndrome 3 (LQTS 3-specific mouse iPS cells and obtained a pure cardiomyocyte population. These cells were investigated by action potential analysis with manual and automatic planar patch clamp technologies, as well as by recording extracellular field potentials using a microelectrode array system. Action potentials and field potentials showed the characteristic prolongation at low heart rates in LQTS 3-specific, but not in wild-type iPS cell-derived cardiomyocytes. Hence, LQTS 3-specific cardiomyocytes can be purified from iPS cells with a lentiviral strategy, maintain the hallmarks of the LQTS 3 disease and can be used for automated electrophysiological characterization and drug screening.

  20. Digitalis and the sick sinus syndrome. Clinical and electrophysiologic documentation of severe toxic effect on sinus node function.

    Science.gov (United States)

    Margolis, J R; Strauss, H C; Miller, H C; Gilbert, M; Wallace, A G

    1975-07-01

    Digoxin, in a common clinical dose and at a low serum level, brought out severe manifestations of sinus node dysfunction in a patient who had previously undergone successful mitral valve replacement. This report presents the results of extensive clinical and electrophysiologic studies of this patient before and after a digoxin challenge. In the absence of cardiac glycoside, the only demonstrable abnormalities of sinus node function were mild resting sinus bradycardia and failure to respond to atropine administration. Responses to isoproterenol administration, programmed premature atrial stimulation, and overdrive pacing at several cycle lengths were normal. Following the administration of intravenous digoxin, 1.025 mg/24 hrs, the resting sinus cycle length increased and the response to overdrive pacing became markedly abnormal. The latter was followed by sinus pauses in excess of six seconds, even at relatively slow overdrive pacing rates. The electrophysiologic and clinical implications of these data are discussed. It is suggested that despite previous reports that digitalis preparations are relatively well tolerated by patients with sick sinus syndrome, caution should be used when administering these drugs to this group of patients.

  1. Software and Hardware Infrastructure for Research in Electrophysiology

    Directory of Open Access Journals (Sweden)

    Roman eMouček

    2014-03-01

    Full Text Available As in other areas of experimental science, operation of electrophysiological laboratory, design and performance of electrophysiological experiments, collection, storage and sharing of experimental data and metadata, analysis and interpretation of these data, and publication of results are time consuming activities. If these activities are well organized and supported by a suitable infrastructure, work efficiency of researchers increases significantly.This article deals with the main concepts, design, and development of software and hardware infrastructure for research in electrophysiology. The described infrastructure has been primarily developed for the needs of neuroinformatics laboratory at the University of West Bohemia, the Czech Republic. However, from the beginning it has been also designed and developed to be open and applicable in laboratories that do similar research.After introducing the laboratory and the whole architectural concept the individual parts of the infrastructure are described. The central element of the software infrastructure is a web-based portal that enables community researchers to store, share, download and search data and metadata from electrophysiological experiments. The data model, domain ontology and usage of semantic web languages and technologies are described. Current data publication policy used in the portal is briefly introduced. The registration of the portal within Neuroscience Information Framework is described. Then the methods used for processing of electrophysiological signals are presented. The specific modifications of these methods introduced by laboratory researches are summarized; the methods are organized into a laboratory workflow. Other parts of the software infrastructure include mobile and offline solutions for data/metadata storing and a hardware stimulator communicating with an EEG amplifier and recording software.

  2. Software and hardware infrastructure for research in electrophysiology.

    Science.gov (United States)

    Mouček, Roman; Ježek, Petr; Vařeka, Lukáš; Rondík, Tomáš; Brůha, Petr; Papež, Václav; Mautner, Pavel; Novotný, Jiří; Prokop, Tomáš; Stěbeták, Jan

    2014-01-01

    As in other areas of experimental science, operation of electrophysiological laboratory, design and performance of electrophysiological experiments, collection, storage and sharing of experimental data and metadata, analysis and interpretation of these data, and publication of results are time consuming activities. If these activities are well organized and supported by a suitable infrastructure, work efficiency of researchers increases significantly. This article deals with the main concepts, design, and development of software and hardware infrastructure for research in electrophysiology. The described infrastructure has been primarily developed for the needs of neuroinformatics laboratory at the University of West Bohemia, the Czech Republic. However, from the beginning it has been also designed and developed to be open and applicable in laboratories that do similar research. After introducing the laboratory and the whole architectural concept the individual parts of the infrastructure are described. The central element of the software infrastructure is a web-based portal that enables community researchers to store, share, download and search data and metadata from electrophysiological experiments. The data model, domain ontology and usage of semantic web languages and technologies are described. Current data publication policy used in the portal is briefly introduced. The registration of the portal within Neuroscience Information Framework is described. Then the methods used for processing of electrophysiological signals are presented. The specific modifications of these methods introduced by laboratory researches are summarized; the methods are organized into a laboratory workflow. Other parts of the software infrastructure include mobile and offline solutions for data/metadata storing and a hardware stimulator communicating with an EEG amplifier and recording software.

  3. [Cardiac evaluation before non-cardiac surgery].

    Science.gov (United States)

    Menzenbach, Jan; Boehm, Olaf

    2016-07-01

    Before non-cardiac surgery, evaluation of cardiac function is no frequent part of surgical treatment. European societies of anesthesiology and cardiology published consensus-guidelines in 2014 to present a reasonable approach for preoperative evaluation. This paper intends to differentiate the composite of perioperative risk and to display the guidelines methodical approach to handle it. Features to identify patients at risk from an ageing population with comorbidities, are the classification of surgical risk, functional capacity and risk indices. Application of diagnostic means, should be used adjusted to this risk estimation. Cardiac biomarkers are useful to discover risk of complications or mortality, that cannot be assessed by clinical signs. After preoperative optimization and perioperative cardiac protection, the observation of the postoperative period remains, to prohibit complications or even death. In consideration of limited resources of intensive care department, postoperative ward rounds beyond intensive care units are considered to be an appropriate instrument to avoid or recognize complications early to reduce postoperative mortality. PMID:27479258

  4. Cardiac metabolism and arrhythmias

    OpenAIRE

    Barth, Andreas S.; Tomaselli, Gordon F.

    2009-01-01

    Sudden cardiac death remains a leading cause of mortality in the Western world, accounting for up to 20% of all deaths in the U.S.1, 2 The major causes of sudden cardiac death in adults age 35 and older are coronary artery disease (70–80%) and dilated cardiomyopathy (10–15%).3 At the molecular level, a wide variety of mechanisms contribute to arrhythmias that cause sudden cardiac death, ranging from genetic predisposition (rare mutations and common polymorphisms in ion channels and structural...

  5. Comprehensive cardiac rehabilitation

    DEFF Research Database (Denmark)

    Kruse, Marie; Hochstrasser, Stefan; Zwisler, Ann-Dorthe O;

    2006-01-01

    OBJECTIVES: The costs of comprehensive cardiac rehabilitation are established and compared to the corresponding costs of usual care. The effect on health-related quality of life is analyzed. METHODS: An unprecedented and very detailed cost assessment was carried out, as no guidelines existed...... and may be as high as euro 1.877. CONCLUSIONS: Comprehensive cardiac rehabilitation is more costly than usual care, and the higher costs are not outweighed by a quality of life gain. Comprehensive cardiac rehabilitation is, therefore, not cost-effective....

  6. An organic transistor-based system for reference-less electrophysiological monitoring of excitable cells

    Science.gov (United States)

    Spanu, A.; Lai, S.; Cosseddu, P.; Tedesco, M.; Martinoia, S.; Bonfiglio, A.

    2015-03-01

    In the last four decades, substantial advances have been done in the understanding of the electrical behavior of excitable cells. From the introduction in the early 70's of the Ion Sensitive Field Effect Transistor (ISFET), a lot of effort has been put in the development of more and more performing transistor-based devices to reliably interface electrogenic cells such as, for example, cardiac myocytes and neurons. However, depending on the type of application, the electronic devices used to this aim face several problems like the intrinsic rigidity of the materials (associated with foreign body rejection reactions), lack of transparency and the presence of a reference electrode. Here, an innovative system based on a novel kind of organic thin film transistor (OTFT), called organic charge modulated FET (OCMFET), is proposed as a flexible, transparent, reference-less transducer of the electrical activity of electrogenic cells. The exploitation of organic electronics in interfacing the living matters will open up new perspectives in the electrophysiological field allowing us to head toward a modern era of flexible, reference-less, and low cost probes with high-spatial and high-temporal resolution for a new generation of in-vitro and in-vivo monitoring platforms.

  7. Electrophysiology Catheter Detection and Reconstruction From Two Views in Fluoroscopic Images.

    Science.gov (United States)

    Hoffmann, Matthias; Brost, Alexander; Koch, Martin; Bourier, Felix; Maier, Andreas; Kurzidim, Klaus; Strobel, Norbert; Hornegger, Joachim

    2016-02-01

    Electrophysiology (EP) studies and catheter ablation have become important treatment options for several types of cardiac arrhythmias. We present a novel image-based approach for automatic detection and 3-D reconstruction of EP catheters where the physician marks the catheter to be reconstructed by a single click in each image. The result can be used to provide 3-D information for enhanced navigation throughout EP procedures. Our approach involves two X-ray projections acquired from different angles, and it is based on two steps: First, we detect the catheter in each view after manual initialization using a graph-search method. Then, the detection results are used to reconstruct a full 3-D model of the catheter based on automatically determined point pairs for triangulation. An evaluation on 176 different clinical fluoroscopic images yielded a detection rate of 83.4%. For measuring the error, we used the coupling distance which is a more accurate quality measure than the average point-wise distance to a reference. For successful outcomes, the 2-D detection error was 1.7 mm ±1.2 mm. Using successfully detected catheters for reconstruction, we obtained a reconstruction error of 1.8 mm ±1.1 mm on phantom data. On clinical data, our method yielded a reconstruction error of 2.2 mm ±2.2 mm. PMID:26441411

  8. Cardiac Risk Assessment

    Science.gov (United States)

    ... to assess cardiac risk include: High-sensitivity C-reactive protein (hs-CRP) : Studies have shown that measuring ... LDL-C but does not respond to typical strategies to lower LDL-C such as diet, exercise, ...

  9. Sudden Cardiac Arrest

    Science.gov (United States)

    ... Heart Risk Factors & Prevention Heart Diseases & Disorders Atrial Fibrillation (AFib) Sudden Cardiac Arrest (SCA) SCA: Who's At Risk? Prevention of SCA What Causes SCA? SCA Awareness Atrial Flutter Heart Block Heart Failure Sick Sinus Syndrome Substances & Heart Rhythm Disorders Symptoms & ...

  10. Socially differentiated cardiac rehabilitation

    DEFF Research Database (Denmark)

    Meillier, Lucette Kirsten; Nielsen, Kirsten Melgaard; Larsen, Finn Breinholt;

    2012-01-01

    to a standard rehabilitation programme (SRP). If patients were identified as socially vulnerable, they were offered an extended version of the rehabilitation programme (ERP). Excluded patients were offered home visits by a cardiac nurse. Concordance principles were used in the individualised programme elements......%. Patients were equally distributed to the SRP and the ERP. No inequality was found in attendance and adherence among referred patients. Conclusions: It seems possible to overcome unequal referral, attendance, and adherence in cardiac rehabilitation by organisation of systematic screening and social......Aim: The comprehensive cardiac rehabilitation (CR) programme after myocardial infarction (MI) improves quality of life and results in reduced cardiac mortality and recurrence of MI. Hospitals worldwide face problems with low participation rates in rehabilitation programmes. Inequality...

  11. Cardiac arrest - cardiopulmonary resuscitation

    Institute of Scientific and Technical Information of China (English)

    Basri Lenjani; Besnik Elshani; Nehat Baftiu; Kelmend Pallaska; Kadir Hyseni; Njazi Gashi; Nexhbedin Karemani; Ilaz Bunjaku; Taxhidin Zaimi; Arianit Jakupi

    2014-01-01

    Objective:To investigate application of cardiopulmonary resuscitation(CPR) measures within the golden minutes inEurope.Methods:The material was taken from theUniversityClinical Center ofKosovo -EmergencyCentre inPristina, during the two(2) year period(2010-2011).The collected date belong to the patients with cardiac arrest have been recorded in the patients' log book protocol at the emergency clinic.Results:During the2010 to2011 in the emergency center of theCUCK inPristina have been treated a total of269 patients with cardiac arrest, of whom159 or59.1% have been treated in2010, and110 patients or40.9% in2011.Of the269 patients treated in the emergency centre,93 or34.6% have exited lethally in the emergency centre, and176 or 65.4% have been transferred to other clinics.In the total number of patients with cardiac arrest, males have dominated with186 cases, or69.1%.The average age of patients included in the survey was56.7 year oldSD±16.0 years.Of the269 patients with cardiac arrest, defibrillation has been applied for93 or34.6% of patients.In the outpatient settings defibrillation has been applied for3 or3.2% of patients.Patients were defibrillated with application of one to four shocks. Of27 cases with who have survived cardiac arrest, none of them have suffered cardiac arrest at home,3 or11.1% of them have suffered cardiac arrest on the street, and24 or88.9% of them have suffered cardiac arrest in the hospital.5 out of27 patients survived have ended with neurological impairment.Cardiac arrest cases were present during all days of the week, but frequently most reported cases have been onMonday with32.0% of cases, and onFriday with24.5% of cases. Conclusions:All survivors from cardiac arrest have received appropriate medical assistance within10 min from attack, which implies that if cardiac arrest occurs near an institution health care(with an opportunity to provide the emergent health care) the rate of survival is higher.

  12. Relative acceleration approach for conduction failure of cardiac excitation propagation on anisotropic curved surfaces

    CERN Document Server

    Chun, Sehun

    2012-01-01

    In cardiac electrophysiology, it is important to predict the necessary conditions for conduction failure, the failure of the cardiac excitation propagation even in the presence of normal excitable tissue, in high-dimensional anisotropic space because these conditions may provide feasible mechanisms for abnormal excitation propagations such as atrial re-entry and, subsequently, atrial fibrillation even without taking into account the time-dependent refractory region. Some conditions of conduction failure have been studied for anisotropy or simple curved surfaces, but the general conditions on anisotropic curved surfaces (anisotropic and curved surface) remain unknown. To predict and analyze conduction failure on anisotropic curved surfaces, a new analytic approach is proposed, called the relative acceleration approach borrowed from spacetime physics. Motivated by a discrete model of cardiac excitation propagation, this approach is based on the hypothesis that a large relative acceleration can translate to a dr...

  13. Recent developments in using mechanistic cardiac modelling for drug safety evaluation.

    Science.gov (United States)

    Davies, Mark R; Wang, Ken; Mirams, Gary R; Caruso, Antonello; Noble, Denis; Walz, Antje; Lavé, Thierry; Schuler, Franz; Singer, Thomas; Polonchuk, Liudmila

    2016-06-01

    On the tenth anniversary of two key International Conference on Harmonisation (ICH) guidelines relating to cardiac proarrhythmic safety, an initiative aims to consider the implementation of a new paradigm that combines in vitro and in silico technologies to improve risk assessment. The Comprehensive In Vitro Proarrhythmia Assay (CiPA) initiative (co-sponsored by the Cardiac Safety Research Consortium, Health and Environmental Sciences Institute, Safety Pharmacology Society and FDA) is a bold and welcome step in using computational tools for regulatory decision making. This review compares and contrasts the state-of-the-art tools from empirical to mechanistic models of cardiac electrophysiology, and how they can and should be used in combination with experimental tests for compound decision making. PMID:26891981

  14. Awareness in cardiac anesthesia.

    LENUS (Irish Health Repository)

    Serfontein, Leon

    2010-02-01

    Cardiac surgery represents a sub-group of patients at significantly increased risk of intraoperative awareness. Relatively few recent publications have targeted the topic of awareness in this group. The aim of this review is to identify areas of awareness research that may equally be extrapolated to cardiac anesthesia in the attempt to increase understanding of the nature and significance of this scenario and how to reduce it.

  15. Cardiac rehabilitation in Germany.

    Science.gov (United States)

    Karoff, Marthin; Held, Klaus; Bjarnason-Wehrens, Birna

    2007-02-01

    The purpose of this review is to give an overview of the rehabilitation measures provided for cardiac patients in Germany and to outline its legal basis and outcomes. In Germany the cardiac rehabilitation system is different from rehabilitation measures in other European countries. Cardiac rehabilitation in Germany since 1885 is based on specific laws and the regulations of insurance providers. Cardiac rehabilitation has predominantly been offered as an inpatient service, but has recently been complemented by outpatient services. A general agreement on the different indications for offering these two services has yet to be reached. Cardiac rehabilitation is mainly offered after an acute cardiac event and bypass surgery. It is also indicated in severe heart failure and special cases of percutaneous coronary intervention. Most patients are men (>65%) and the age at which events occur is increasing. The benefits obtained during the 3-4 weeks after an acute event, and confirmed in numerous studies, are often later lost under 'usual care' conditions. Many attempts have been made by rehabilitation institutions to improve this deficit by providing intensive aftercare. One instrument set up to achieve this is the nationwide institution currently comprising more than 6000 heart groups with approximately 120000 outpatients. After coronary artery bypass grafting or acute coronary syndrome cardiac rehabilitation can usually be started within 10 days. The multidisciplinary rehabilitation team consists of cardiologists, psychologists, exercise therapists, social workers, nutritionists and nurses. The positive effects of cardiac rehabilitation are also important economically, for example, for the improvement of secondary prevention and vocational integration. PMID:17301623

  16. Cardiac tumours in infancy

    OpenAIRE

    Yadava, O.P.

    2012-01-01

    Cardiac tumours in infancy are rare and are mostly benign with rhabdomyomas, fibromas and teratomas accounting for the majority. The presentation depends on size and location of the mass as they tend to cause cavity obstruction or arrhythmias. Most rhabdomyomas tend to regress spontaneously but fibromas and teratomas generally require surgical intervention for severe haemodynamic or arrhythmic complications. Other relatively rare cardiac tumours too are discussed along with an Indian perspect...

  17. Infected cardiac hydatid cyst

    OpenAIRE

    Ceviz, M; Becit, N; Kocak, H.

    2001-01-01

    A 24 year old woman presented with chest pain and palpitation. The presence of a semisolid mass—an echinococcal cyst or tumour—in the left ventricular apex was diagnosed by echocardiography, computed tomography, and magnetic resonance imaging. The infected cyst was seen at surgery. The cyst was removed successfully by using cardiopulmonary bypass with cross clamp.


Keywords: cardiac hydatid cyst; infected cardiac hydatid cyst

  18. Nonlinear dynamics of the heartbeat II. Subharmonic bifurcations of the cardiac interbeat interval in sinus node disease

    Science.gov (United States)

    Goldberger, Ary L.; Bhargava, Valmik; West, Bruce J.; Mandell, Arnold J.

    1985-10-01

    Changing the coupling of electronic relaxation oscillators may be associated with the emergence of complex periodic behavior. The electrocardiographic record of a patient with the “sick sinus syndrome” demonstrated periodic behavior including subharmonic bifurcations in an attractor of his interbeat interval. Such nonlinear dynamics which may emerge from alterations in the coupling of oscillating pacemakers are not predicted by traditional models in cardiac electrophysiology. An understanding of the nonlinear behavior of physical and mathematical systems may generalize to pathophysiological processes.

  19. Carbon nanotubes instruct physiological growth and functionally mature syncytia: nongenetic engineering of cardiac myocytes.

    Science.gov (United States)

    Martinelli, Valentina; Cellot, Giada; Toma, Francesca Maria; Long, Carlin S; Caldwell, John H; Zentilin, Lorena; Giacca, Mauro; Turco, Antonio; Prato, Maurizio; Ballerini, Laura; Mestroni, Luisa

    2013-07-23

    Myocardial tissue engineering currently represents one of the most realistic strategies for cardiac repair. We have recently discovered the ability of carbon nanotube scaffolds to promote cell division and maturation in cardiomyocytes. Here, we test the hypothesis that carbon nanotube scaffolds promote cardiomyocyte growth and maturation by altering the gene expression program, implementing the cell electrophysiological properties and improving networking and maturation of functional syncytia. In our study, we combine microscopy, biological and electrophysiological methodologies, and calcium imaging, to verify whether neonatal rat ventricular myocytes cultured on substrates of multiwall carbon nanotubes acquire a physiologically more mature phenotype compared to control (gelatin). We show that the carbon nanotube substrate stimulates the induction of a gene expression profile characteristic of terminal differentiation and physiological growth, with a 2-fold increase of α-myosin heavy chain (P carbon nanotubes appear to exert a protective effect against the pathologic stimulus of phenylephrine. Finally, cardiomyocytes on carbon nanotubes demonstrate a more mature electrophysiological phenotype of syncytia and intracellular calcium signaling. Thus, carbon nanotubes interacting with cardiomyocytes have the ability to promote physiological growth and functional maturation. These properties are unique in the current vexing field of tissue engineering, and offer unprecedented perspectives in the development of innovative therapies for cardiac repair.

  20. Electrophysiological Evaluation of Oropharyngeal Dysphagia in Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Cumhur Ertekin

    2014-10-01

    Full Text Available Parkinson’s disease (PD is a chronic, neurodegenerative movement disorder that typically affects elderly patients. Swallowing disorders are highly prevalent in PD and can have grave consequences, including pneumonia, malnutrition, dehydration and mortality. Neurogenic dysphagia in PD can manifest with both overt clinical symptoms or silent dysphagia. Regardless, early diagnosis and objective follow-up of dysphagia in PD is crucial for timely and appropriate care for these patients. In this review, we provide a comprehensive summary of the electrophysiological methods that can be used to objectively evaluate dysphagia in PD. We discuss the electrophysiological abnormalities that can be observed in PD, their clinical correlates and the pathophysiology underlying these findings.

  1. Acute Inflammatory Demyelinating Polyneuropathy in Children; Clinical and Electrophysiologic Findings

    Directory of Open Access Journals (Sweden)

    Seyed-Hasan Tonekaboni

    2009-03-01

    Full Text Available Objective:The aim of this study was to evaluate the electrophysiologic findings of Guillain Barre Syndrome (GBS in children and their relation with clinical progress of the disease. Methods:Twenty-three children with GBS were evaluated between 2005 and 2007. Electrophysiologic evaluations were performed at admission and one month later. Findings: Five patients needed respirator, 15 were bedridden, 1 developed recurrence 6 months later, and 2 experienced chronic GBS. The most common findings included: decreased amplitude of muscle action potential (CMAP (96%, increased distal latency (74%, increased F wave latency (69%, and decreased nerve conduction velocity (NCV (61%. Sensory nerve conduction (evaluating sural nerve was normal in 78% of the cases. These measures did not significantly change after 1 month. Conclusion:Electrodiagnostic evaluations are helpful at the primary stages of GBS for diagnosis. Fibrillation potentials and positive sharp waves showing denervation and axonal injury are presentative of longer duration of the disease and a worse prognosis.

  2. Reversible electrophysiological abnormalities in acute secondary hyperkalemic paralysis

    Directory of Open Access Journals (Sweden)

    Karkal R Naik

    2012-01-01

    Full Text Available Hyperkalemia manifests clinically with acute neuromuscular paralysis, which can simulate Guillain Barré syndrome (GBS and other causes of acute flaccid paralysis. Primary hyperkalemic paralysis occurs from genetic defects in the sodium channel, and secondary hyperkalemic paralysis (SHP from diverse causes including renal dysfunction, potassium retaining drugs, Addison′s disease, etc. Clinical characteristics of SHP have been addressed in a number of publications. However, electrophysiological evaluations of these patients during neuromuscular paralysis are infrequently reported and have demonstrated features of demyelination. The clinical features and electrophysiological abnormalities in secondary hyperkalemia mimic GBS, and pose diagnostic challenges. We report the findings of nerve conduction studies in a middle-aged man who was admitted with rapidly reversible acute quadriplegia resulting from secondary hyperkalemic paralysis.

  3. Breadboard Amplifier: Building and Using Simple Electrophysiology Equipment.

    Science.gov (United States)

    Crisp, Kevin M; Lin, Hunter; Prosper, Issa

    2016-01-01

    Electrophysiology is a valuable skill for the neuroscientist, but the learning curve for students can be steep. Here we describe a very simple electromyography (EMG) amplifier that can be built from scratch by students with no electronics experience in about 30 minutes, making it ideal for incorporating into a laboratory activity. With few parts and no adjustments except the gain, students can begin physiology experiments quickly while having the satisfaction of having built the equipment themselves. Because the output of the circuit goes to a computer sound card, students can listen to electrophysiological activity as they see it on the computer screen, a feature many of our students greatly appreciated. Various applications are discussed, including dual channel recording, using streaming media platforms with remote lab partners and acquiring data in the field on a smart phone. Our students reported that they enjoyed being able to build a working device and using it to record from their own muscles. PMID:27385921

  4. Nanomaterial-Enabled Dry Electrodes for Electrophysiological Sensing: A Review

    Science.gov (United States)

    Yao, Shanshan; Zhu, Yong

    2016-04-01

    Long-term, continuous, and unsupervised tracking of physiological data is becoming increasingly attractive for health/wellness monitoring and ailment treatment. Nanomaterials have recently attracted extensive attention as building blocks for flexible/stretchable conductors and are thus promising candidates for electrophysiological electrodes. Here we provide a review on nanomaterial-enabled dry electrodes for electrophysiological sensing, focusing on electrocardiography (ECG). The dry electrodes can be classified into contact surface electrodes, contact-penetrating electrodes, and noncontact capacitive electrodes. Different types of electrodes including their corresponding equivalent electrode-skin interface models and the sources of the noise are first introduced, followed by a review on recent developments of dry ECG electrodes based on various nanomaterials, including metallic nanowires, metallic nanoparticles, carbon nanotubes, and graphene. Their fabrication processes and performances in terms of electrode-skin impedance, signal-to-noise ratio, resistance to motion artifacts, skin compatibility, and long-term stability are discussed.

  5. Pants on fire: the electrophysiological signature of telling a lie.

    Science.gov (United States)

    Pfister, Roland; Foerster, Anna; Kunde, Wilfried

    2014-01-01

    Even though electroencephalography has played a prominent role for lie detection via personally relevant information, the electrophysiological signature of active lying is still elusive. We addressed this signature with two experiments in which participants helped a virtual police officer to locate a knife. Crucially, before this response, they announced whether they would lie or tell the truth about the knife's location. This design allowed us to study the signature of lie-telling in the absence of rare and personally significant oddball stimuli that are typically used for lie detection via electrophysiological markers, especially the P300 component. Our results indicate that active lying attenuated P300 amplitudes as well as N200 amplitudes for such non-oddball stimuli. These results support accounts that stress the high cognitive demand of lie-telling, including the need to suppress the truthful response and to generate a lie.

  6. The Growing Culture of a Minimally Fluoroscopic Approach in Electrophysiology Lab

    Directory of Open Access Journals (Sweden)

    Michela Casella; Eleonora Russo; Francesca Pizzamiglio; Sergio Conti; Ghaliah Al-Mohani; Daniele Colombo; Victor Casula; Yuri D�Alessandra; Viviana Biagioli; Corrado Carbucicchio; Stefania Riva; Gaetano Fassini; Massimo Moltrasio; Fabrizio Tundo; Martina Zucchetti; Benedetta Majocchi; Vittoria Marino; Giovanni Forleo; Pasquale Santangeli; Luigi Di Biase; Antonio Dello Russo; Andrea Natale; Claudio Tondo

    2014-08-01

    Full Text Available As the first imaging modality of the living human body, X-ray fluoroscopic imaging has been the most important technical tool in modern medicine (Roentgen. It allowed one to see the inside of the body and, after contrast injection, even of soft tissues like the beating heart. To date, most of interventional procedures in cardiology are carried out under fluoroscopic imaging guidance. Besides other peri-interventional risks, radiation exposure should be considered for its stochastic (inducing malignancy and deterministic effects on health (tissue reactions like erythema, hair loss and cataracts. Due to increased interventional procedures and imaging studies in the last decades, patients are being exposed to a substantial amount of radiation over their lifetime. Some procedures like catheter ablation of atrial fibrillation frequently requires cardiac computed tomography (CT scan before the intervention and more than one ablation procedure, thereby adding a substantial amount of radiation. On an average, a complex cardiac radiofrequency ablation corresponds to 750 chest X-rays (range 100–2850. Recently, attention has been applied to the radiation exposure of the catheter lab staff who expose themselves professionally. Being close to the patient during an interventional procedure, the first hand operator is exposed to scattered radiation, whilst other health care professionals are better protected by their position at a greater distance to the radiation source and the patient itself. Besides the associated X-ray exposure, the main limitation of fluoroscopy is that in complex arrhythmias fluoroscopy only provides two-dimensional (2D representations of three dimensional (3D anatomical structures as potentials targets for ablation. With the evolution of technology, new non fluoroscopic 3D mapping systems from the late 1990s have been an alternative to fluoroscopy alone in electrophysiology world. Infact constructing a virtual real time 3D map

  7. Electrophysiological correlates of non-stationary BOLD functional connectivity fluctuations

    OpenAIRE

    Tagliazucchi, Enzo; von Wegner, Frederic; Morzelewski, Astrid; Brodbeck, Verena; Laufs, Helmut

    2012-01-01

    Spontaneous fluctuations of the BOLD (Blood Oxygen Level-Dependent) signal, measured with fMRI (functional Magnetic Resonance Imaging), display a rich and neurobiologically relevant functional connectivity structure. This structure is usually revealed using time averaging methods, which prevent the detection of functional connectivity changes over time. In this work we studied the electrophysiological correlates of dynamical BOLD functional connectivity fluctuations, by means of long (approx....

  8. Computational Intelligence Techniques for Electro-Physiological Data Analysis

    OpenAIRE

    Riera Sardà, Alexandre

    2012-01-01

    This work contains the efforts I have made in the last years in the field of Electrophysiological data analysis. Most of the work has been done at Starlab Barcelona S.L. and part of it at the Neurodynamics Laboratory of the Department of Psychiatry and Clinical Psychobiology of the University of Barcelona. The main work deals with the analysis of electroencephalography (EEG) signals, although other signals, such as electrocardiography (ECG), electroculography (EOG) and electromiography (EMG) ...

  9. Electrophysiological observations on the human pudendo-anal reflex.

    OpenAIRE

    Varma, J S; Smith, A N; McInnes, A

    1986-01-01

    A reproducible electrophysiological technique is described to determine the latency of reflex contraction of the external anal sphincter in response to stimulation of the dorsal genital nerve: the pudendo-anal reflex. This was studied in 38 asymptomatic control subjects and 20 women with neurogenic faecal incontinence, supplemented by determination of the mean motor unit potential duration (MUPD) of the external anal sphincter and anorectal manometry. The reflex latency in the control group w...

  10. Human enteric neurons: morphological, electrophysiological, and neurochemical identification

    OpenAIRE

    Carbone, S E; Jovanovska, V; Nurgali, K; Brookes, S J H

    2014-01-01

    Background Access to tissue, difficulties with dissection, and poor visibility of enteric ganglia have hampered electrophysiological recordings of human enteric neurons. Here, we report a method to combine intracellular recording with simultaneous morphological identification of neurons in the intact myenteric plexus of human colon ex vivo. Methods Specimens of human colon were dissected into flat-sheet preparations with the myenteric plexus exposed. Myenteric neurons were impaled with conven...

  11. Galvanic Vestibular Stimulation Modulates the Electrophysiological Response During Face Processing

    OpenAIRE

    Wilkinson, David T.; Ferguson, Heather J.; Worley, Alan

    2012-01-01

    Although galvanic vestibular stimulation (GVS) is known to affect the speed and accuracy of visual judgments, the underlying electrophysiological response has not been explored. In the present study, we therefore investigated the effect of GVS on the N170 event-related potential, a marker commonly associated with early visual structural encoding. To elicit the waveform, participants distinguished famous from non-famous faces that were presented in either upright or inverted orientation. Relat...

  12. Effects of Morphology Constraint on Electrophysiological Properties of Cortical Neurons

    OpenAIRE

    Geng Zhu; Liping Du; Lei Jin; Andreas Offenhäusser

    2016-01-01

    There is growing interest in engineering nerve cells in vitro to control architecture and connectivity of cultured neuronal networks or to build neuronal networks with predictable computational function. Pattern technologies, such as micro-contact printing, have been developed to design ordered neuronal networks. However, electrophysiological characteristics of the single patterned neuron haven’t been reported. Here, micro-contact printing, using polyolefine polymer (POP) stamps with high res...

  13. Electrophysiological evaluation of ulnar nerve in carpal tunnel syndrome

    Institute of Scientific and Technical Information of China (English)

    刘娜

    2014-01-01

    Objective To evaluate the impairment of ulnar nerve and its relationship with sensory symptoms in the ulnar territory in patients with carpal tunnel syndrome(CTS)through electrophysiological approach.Methods We retrospectively reviewed 55 cases with CTS admitted in our hospital from January 2012 to February 2013.Patients with CTS were graded as mild-moderate(35 cases)andsevere(20 cases)according to Stevens standard and were divided into symptomatic and non-symptomatic group according

  14. Clinical and Electrophysiological Report of a Unilateral Retinitis Pigmentosa Case

    OpenAIRE

    Sedaghat,, Sanaz; Askari S.A; Afshar R

    2014-01-01

    Introduction: To describe clinical and electrophysiological features of a patient with unilateral Retinitis Pigmentosa (RP). Case: A 29-year-old female with a long history of progressive visual disturbance in the right eye has undergone multiple eye examinations during the past eight years. There was nothing noticeable in her past medical and ocular history. Comprehensive eye examinations were done in the first visit. All data was suggestive of right eye RP. Posterior segment fundal examinati...

  15. Investigation of Electrophysiological Patterns and Multiple Treatments in Tinnitus

    OpenAIRE

    Cartocci, Giulia

    2014-01-01

    Tinnitus is the most common auditory desorder, it is defined as a sound sensation in the absence of any external sound source. Sleep disturbances and depression are symptoms very often present in tinnitus patients. Starting from this observation, in the present thesis two electrophysiological approaches to tinnitus study are described: the former concerns sleep architecture pattern investigation in tinnitus patients, and the second concerns an index of serotonin activity in the auditory corte...

  16. Effects of Morphology Constraint on Electrophysiological Properties of Cortical Neurons

    Science.gov (United States)

    Zhu, Geng; Du, Liping; Jin, Lei; Offenhäusser, Andreas

    2016-04-01

    There is growing interest in engineering nerve cells in vitro to control architecture and connectivity of cultured neuronal networks or to build neuronal networks with predictable computational function. Pattern technologies, such as micro-contact printing, have been developed to design ordered neuronal networks. However, electrophysiological characteristics of the single patterned neuron haven’t been reported. Here, micro-contact printing, using polyolefine polymer (POP) stamps with high resolution, was employed to grow cortical neurons in a designed structure. The results demonstrated that the morphology of patterned neurons was well constrained, and the number of dendrites was decreased to be about 2. Our electrophysiological results showed that alterations of dendritic morphology affected firing patterns of neurons and neural excitability. When stimulated by current, though both patterned and un-patterned neurons presented regular spiking, the dynamics and strength of the response were different. The un-patterned neurons exhibited a monotonically increasing firing frequency in response to injected current, while the patterned neurons first exhibited frequency increase and then a slow decrease. Our findings indicate that the decrease in dendritic complexity of cortical neurons will influence their electrophysiological characteristics and alter their information processing activity, which could be considered when designing neuronal circuitries.

  17. Development of Pacing, Electrophysiology and Defibrillation in India

    OpenAIRE

    Nair, Mohan; Francis, Johnson; Venugopal, K

    2002-01-01

    History of cardiac pacing in India dates back to late 1960s. Kar1 reported that cardiac pacing was introduced in India in 1966. Basu2 while discussing on cardiac pacemaking in Calcutta, mentions that the first pacing was performed in April 1967 at the Institute of Post Graduate Medical Education and Research (IPGME&R). Bhatia et al3 started pacemaker implantation at AIIMS, New Delhi in 1968. Their first patient was a doctor from Assam and the pulse generator was supplied by Medtronic Inc. Th...

  18. Interventional guidance for cardiac resynchronization therapies: merging anatomic X-ray imaging with functional ultrasound imaging based on mutually-shared landmarks

    Energy Technology Data Exchange (ETDEWEB)

    Manzke, R.; Shechter, G.; Gutierrez, L.; Chan, R.C. [Philips Research North America, Briarcliff Manor, NY (United States); Tournoux, F.; Singh, J.; Picard, M. [Dept. of Cardiology, Massachusetts General Hospital, Harvard Medical School (United States); Brink, B. v.d.; Boomen, R. v.d. [Philips Medical System, Best (Netherlands); Gerard, O. [Philips Medical Systems, Paris (France)

    2007-06-15

    Detailed knowledge of cardiac anatomy and function is required for complex cardiac electrophysiology interventions. Cardiac resynchronization therapies (CRT), for example, requires information about coronary venous anatomy for left ventricular lead placement. In CRT, heart failure patients are equipped with dual-chamber pacemakers in order to improve cardiac output and heart failure symptoms. Cardiac function is mainly assessed with Ultrasound imaging. Fusion of complementary information from X-ray and ultrasound is an essential step towards fully utilizing all available information for CRT guidance. We present an approach for fusion of anatomical information (coronary vein structure) from X-ray with functional information (left ventricular deformation and dynamics) from ultrasound. We propose an image-based fusion approach based on mutually-shared landmarks which enable registration of both imaging spaces without the need for external tracking. (orig.)

  19. [Negative symptoms of schizophrenia: from electrophysiology to electrotherapy].

    Science.gov (United States)

    Micoulaud Franchi, J-A; Quiles, C; Belzeaux, R; Adida, M; Azorin, J-M

    2015-12-01

    The aim of this review of the literature is to summarize the state of the knowledge concerning the relationship between negative symptoms in schizophrenia, electrophysiology and electrotherapy. The scientific literature search of international articles was performed during August and September 2015 using the PubMed electronic database. We used the following MeSH terms: "Negative symptoms", "Schizophrenia", "Electrophysiology", "Neurophysiology", "EEG power", "Alpha rhythm", "Transcranial magnetic stimulation", "Transcranial direct current stimulation", "Electroconvulsive therapy", "Neurofeedback", "Vagus Nerve Stimulation", "Deep Brain Stimulation", and "State dependent". Negative symptoms in schizophrenia are associated with altered activity in prefrontal cortex in functional neuroimaging studies. This is in line with electrophysiological measurements that found a change in EEG spectral power in the alpha frequency band over prefrontal brain regions. The notion of functional hypofrontality has led to hypotheses that electrotherapy applied to the prefrontal cortex may be an effective treatment of negative symptoms in schizophrenia. Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) were used to increase cortical activity in schizophrenia and achieve a clinical effect on negative symptoms. Three meta-analyses confirmed, with a moderate effect size, that rTMS is an effective treatment option for negative symptoms in schizophrenia. The two subsequently published prospective multicenter studies, however, found opposite results from each other. Two randomized controlled studies suggested that tDCS is an effective treatment option for negative symptoms. There is no study on the efficacy of neurofeedback, vagal nerve stimulation or deep brain stimulation on negative symptoms in schizophrenia. Additional studies are needed to confirm the efficacy of rTMS and tDCS on negative symptoms in schizophrenia. Influencing factors

  20. [Negative symptoms of schizophrenia: from electrophysiology to electrotherapy].

    Science.gov (United States)

    Micoulaud Franchi, J-A; Quiles, C; Belzeaux, R; Adida, M; Azorin, J-M

    2015-12-01

    The aim of this review of the literature is to summarize the state of the knowledge concerning the relationship between negative symptoms in schizophrenia, electrophysiology and electrotherapy. The scientific literature search of international articles was performed during August and September 2015 using the PubMed electronic database. We used the following MeSH terms: "Negative symptoms", "Schizophrenia", "Electrophysiology", "Neurophysiology", "EEG power", "Alpha rhythm", "Transcranial magnetic stimulation", "Transcranial direct current stimulation", "Electroconvulsive therapy", "Neurofeedback", "Vagus Nerve Stimulation", "Deep Brain Stimulation", and "State dependent". Negative symptoms in schizophrenia are associated with altered activity in prefrontal cortex in functional neuroimaging studies. This is in line with electrophysiological measurements that found a change in EEG spectral power in the alpha frequency band over prefrontal brain regions. The notion of functional hypofrontality has led to hypotheses that electrotherapy applied to the prefrontal cortex may be an effective treatment of negative symptoms in schizophrenia. Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) were used to increase cortical activity in schizophrenia and achieve a clinical effect on negative symptoms. Three meta-analyses confirmed, with a moderate effect size, that rTMS is an effective treatment option for negative symptoms in schizophrenia. The two subsequently published prospective multicenter studies, however, found opposite results from each other. Two randomized controlled studies suggested that tDCS is an effective treatment option for negative symptoms. There is no study on the efficacy of neurofeedback, vagal nerve stimulation or deep brain stimulation on negative symptoms in schizophrenia. Additional studies are needed to confirm the efficacy of rTMS and tDCS on negative symptoms in schizophrenia. Influencing factors

  1. Cardiac involvement in myotonic muscular dystrophy (Steinert's disease): a prospective study of 25 patients

    International Nuclear Information System (INIS)

    The presence, degree and frequency of disorders of cardiac conduction and rhythm and of regional or global myocardial dystrophy or myotonia have not previously been studied prospectively and systematically in the same population of patients with myotonic dystrophy. Accordingly, 25 adults with classic Steinert's disease underwent electrocardiography, 24-hour ambulatory electrocardiography, vectorcardiography, chest x-rays, echocardiography, electrophysiologic studies, and technetium-99m angiography. Clinically important cardiac manifestations of myotonic dystrophy reside in specialized tissues rather than in myocardium. Involvement is relatively specific, primarily assigned to the His-Purkinje system. The cardiac muscle disorder takes the form of dystrophy rather than myotonia, and is not selective, appearing with approximately equal distribution in all 4 chambers. Myocardial dystrophy seldom results in clinically overt ventricular failure, but may be responsible for atrial and ventricular arrhythmias. Since myotonic dystrophy is genetically transmitted, a primary biochemical defect has been proposed with complete expression of the gene toward striated muscle tissue, whether skeletal or cardiac. Specialized cardiac tissue and myocardium have close, if not identical, embryologic origins, so it is not surprising that the genetic marker affects both. Cardiac involvement is therefore an integral part of myotonic dystrophy, targeting particularly the infranodal conduction system, to a lesser extent the sinus node, and still less specifically, the myocardium

  2. Reactive Oxygen Species, Endoplasmic Reticulum Stress and Mitochondrial Dysfunction: The Link with Cardiac Arrhythmogenesis

    Science.gov (United States)

    Tse, Gary; Yan, Bryan P.; Chan, Yin W. F.; Tian, Xiao Yu; Huang, Yu

    2016-01-01

    Background: Cardiac arrhythmias represent a significant problem globally, leading to cerebrovascular accidents, myocardial infarction, and sudden cardiac death. There is increasing evidence to suggest that increased oxidative stress from reactive oxygen species (ROS), which is elevated in conditions such as diabetes and hypertension, can lead to arrhythmogenesis. Method: A literature review was undertaken to screen for articles that investigated the effects of ROS on cardiac ion channel function, remodeling and arrhythmogenesis. Results: Prolonged endoplasmic reticulum stress is observed in heart failure, leading to increased production of ROS. Mitochondrial ROS, which is elevated in diabetes and hypertension, can stimulate its own production in a positive feedback loop, termed ROS-induced ROS release. Together with activation of mitochondrial inner membrane anion channels, it leads to mitochondrial depolarization. Abnormal function of these organelles can then activate downstream signaling pathways, ultimately culminating in altered function or expression of cardiac ion channels responsible for generating the cardiac action potential (AP). Vascular and cardiac endothelial cells become dysfunctional, leading to altered paracrine signaling to influence the electrophysiology of adjacent cardiomyocytes. All of these changes can in turn produce abnormalities in AP repolarization or conduction, thereby increasing likelihood of triggered activity and reentry. Conclusion: ROS plays a significant role in producing arrhythmic substrate. Therapeutic strategies targeting upstream events include production of a strong reducing environment or the use of pharmacological agents that target organelle-specific proteins and ion channels. These may relieve oxidative stress and in turn prevent arrhythmic complications in patients with diabetes, hypertension, and heart failure. PMID:27536244

  3. Modeling Electrophysiological Coupling and Fusion between Human Mesenchymal Stem Cells and Cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Joshua Mayourian

    2016-07-01

    Full Text Available Human mesenchymal stem cell (hMSC delivery has demonstrated promise in preclinical and clinical trials for myocardial infarction therapy; however, broad acceptance is hindered by limited understanding of hMSC-human cardiomyocyte (hCM interactions. To better understand the electrophysiological consequences of direct heterocellular connections between hMSCs and hCMs, three original mathematical models were developed, representing an experimentally verified triad of hMSC families with distinct functional ion channel currents. The arrhythmogenic risk of such direct electrical interactions in the setting of healthy adult myocardium was predicted by coupling and fusing these hMSC models to the published ten Tusscher midcardial hCM model. Substantial variations in action potential waveform-such as decreased action potential duration (APD and plateau height-were found when hCMs were coupled to the two hMSC models expressing functional delayed rectifier-like human ether à-go-go K+ channel 1 (hEAG1; the effects were exacerbated for fused hMSC-hCM hybrid cells. The third family of hMSCs (Type C, absent of hEAG1 activity, led to smaller single-cell action potential alterations during coupling and fusion, translating to longer tissue-level mean action potential wavelength. In a simulated 2-D monolayer of cardiac tissue, re-entry vulnerability with low (5% hMSC insertion was approximately eight-fold lower with Type C hMSCs compared to hEAG1-functional hMSCs. A 20% decrease in APD dispersion by Type C hMSCs compared to hEAG1-active hMSCs supports the claim of reduced arrhythmogenic potential of this cell type with low hMSC insertion. However, at moderate (15% and high (25% hMSC insertion, the vulnerable window increased independent of hMSC type. In summary, this study provides novel electrophysiological models of hMSCs, predicts possible arrhythmogenic effects of hMSCs when directly coupled to healthy hCMs, and proposes that isolating a subset of hMSCs absent

  4. Modeling Electrophysiological Coupling and Fusion between Human Mesenchymal Stem Cells and Cardiomyocytes.

    Science.gov (United States)

    Mayourian, Joshua; Savizky, Ruben M; Sobie, Eric A; Costa, Kevin D

    2016-07-01

    Human mesenchymal stem cell (hMSC) delivery has demonstrated promise in preclinical and clinical trials for myocardial infarction therapy; however, broad acceptance is hindered by limited understanding of hMSC-human cardiomyocyte (hCM) interactions. To better understand the electrophysiological consequences of direct heterocellular connections between hMSCs and hCMs, three original mathematical models were developed, representing an experimentally verified triad of hMSC families with distinct functional ion channel currents. The arrhythmogenic risk of such direct electrical interactions in the setting of healthy adult myocardium was predicted by coupling and fusing these hMSC models to the published ten Tusscher midcardial hCM model. Substantial variations in action potential waveform-such as decreased action potential duration (APD) and plateau height-were found when hCMs were coupled to the two hMSC models expressing functional delayed rectifier-like human ether à-go-go K+ channel 1 (hEAG1); the effects were exacerbated for fused hMSC-hCM hybrid cells. The third family of hMSCs (Type C), absent of hEAG1 activity, led to smaller single-cell action potential alterations during coupling and fusion, translating to longer tissue-level mean action potential wavelength. In a simulated 2-D monolayer of cardiac tissue, re-entry vulnerability with low (5%) hMSC insertion was approximately eight-fold lower with Type C hMSCs compared to hEAG1-functional hMSCs. A 20% decrease in APD dispersion by Type C hMSCs compared to hEAG1-active hMSCs supports the claim of reduced arrhythmogenic potential of this cell type with low hMSC insertion. However, at moderate (15%) and high (25%) hMSC insertion, the vulnerable window increased independent of hMSC type. In summary, this study provides novel electrophysiological models of hMSCs, predicts possible arrhythmogenic effects of hMSCs when directly coupled to healthy hCMs, and proposes that isolating a subset of hMSCs absent of hEAG1

  5. Role of Sodium Channel on Cardiac Action Potential

    Directory of Open Access Journals (Sweden)

    S. H. Sabzpoushan

    2012-06-01

    Full Text Available Sudden cardiac death is a major cause of death worldwide. In most cases, it's caused by abnormal action potential propagation that leads to cardiac arrhythmia. The aim of this article is to study the abnormal action potential propagation through sodium ion concentration variations. We use a new electrophysiological model that is both detailed and computationally efficient. This efficient model is based on the partial differential equation method. The central finite difference method is used for numerical solving of the two-dimensional (2D wave propagation equation. Simulations are implemented in two stages, as a single cardiac cell and as a two-dimensional grid of cells. In both stages, the normal action potential formation in case of a single cell and it's normal propagation in case of a two-dimensional grid of cells were simulated with nominal sodium ion conductance. Then, the effect of sodium ion concentration on the action potential signal was studied by reducing the sodium ion conductance. It is concluded that reducing the sodium ion conductance, decreases both passing ability and conduction velocity of the action potential wave front.

  6. Cardiac Mechano-Gated Ion Channels and Arrhythmias.

    Science.gov (United States)

    Peyronnet, Rémi; Nerbonne, Jeanne M; Kohl, Peter

    2016-01-22

    Mechanical forces will have been omnipresent since the origin of life, and living organisms have evolved mechanisms to sense, interpret, and respond to mechanical stimuli. The cardiovascular system in general, and the heart in particular, is exposed to constantly changing mechanical signals, including stretch, compression, bending, and shear. The heart adjusts its performance to the mechanical environment, modifying electrical, mechanical, metabolic, and structural properties over a range of time scales. Many of the underlying regulatory processes are encoded intracardially and are, thus, maintained even in heart transplant recipients. Although mechanosensitivity of heart rhythm has been described in the medical literature for over a century, its molecular mechanisms are incompletely understood. Thanks to modern biophysical and molecular technologies, the roles of mechanical forces in cardiac biology are being explored in more detail, and detailed mechanisms of mechanotransduction have started to emerge. Mechano-gated ion channels are cardiac mechanoreceptors. They give rise to mechano-electric feedback, thought to contribute to normal function, disease development, and, potentially, therapeutic interventions. In this review, we focus on acute mechanical effects on cardiac electrophysiology, explore molecular candidates underlying observed responses, and discuss their pharmaceutical regulation. From this, we identify open research questions and highlight emerging technologies that may help in addressing them.

  7. High-order finite element methods for cardiac monodomain simulations

    Directory of Open Access Journals (Sweden)

    Kevin P Vincent

    2015-08-01

    Full Text Available Computational modeling of tissue-scale cardiac electrophysiology requires numerically converged solutions to avoid spurious artifacts. The steep gradients inherent to cardiac action potential propagation necessitate fine spatial scales and therefore a substantial computational burden. The use of high-order interpolation methods has previously been proposed for these simulations due to their theoretical convergence advantage. In this study, we compare the convergence behavior of linear Lagrange, cubic Hermite, and the newly proposed cubic Hermite-style serendipity interpolation methods for finite element simulations of the cardiac monodomain equation. The high-order methods reach converged solutions with fewer degrees of freedom and longer element edge lengths than traditional linear elements. Additionally, we propose a dimensionless number, the cell Thiele modulus, as a more useful metric for determining solution convergence than element size alone. Finally, we use the cell Thiele modulus to examine convergence criteria for obtaining clinically useful activation patterns for applications such as patient-specific modeling where the total activation time is known a priori.

  8. The Insular Cortex and the Regulation of Cardiac Function.

    Science.gov (United States)

    Oppenheimer, Stephen; Cechetto, David

    2016-04-01

    Cortical representation of the heart challenges the orthodox view that cardiac regulation is confined to stereotyped, preprogrammed and rigid responses to exteroceptive or interoceptive environmental stimuli. The insula has been the region most studied in this regard; the results of clinical, experimental, and functional radiological studies show a complex interweave of activity with patterns dynamically varying regarding lateralization and antero-posterior distribution of responsive insular regions. Either acting alone or together with other cortical areas including the anterior cingulate, medial prefrontal, and orbito-frontal cortices as part of a concerted network, the insula can imbue perceptions with autonomic color providing emotional salience, and aiding in learning and behavioral decision choice. In these functions, cardiovascular input and the right anterior insula appear to play an important, if not pivotal role. At a more basic level, the insula gauges cardiovascular responses to exteroceptive and interoceptive stimuli, taking into account memory, cognitive, and reflexive constructs thereby ensuring appropriate survival responses and maintaining emotional and physiological homeostasis. When acquired derangements to the insula occur after stroke, during a seizure or from abnormal central processing of interoceptive or exteroceptive environmental cues as in psychiatric disorders, serious consequences can arise including cardiac electrophysiological, structural and contractile dysfunction and sudden cardiac death. PMID:27065176

  9. A vertical approach to cardiac arrhythmias.

    Science.gov (United States)

    Vaughan Williams, E M

    1987-10-01

    Study of cardiac arrhythmia may be pursued vertically, as up the rungs of a ladder, from symptom to ECG, to EPS, to local lesion, to intracellular metabolism and to alterations of the latter and their effects on charge-transfer by ions across the cell membrane. Raised intracellular cAMP and calcium concentrations are responses to normal physiological controls, and highly abnormal ECGs occur in normal people under stress without progressing to life threatening arrhythmias, yet do so in susceptible individuals. Conversely, appropriate stimulation can precipitate ventricular fibrillation in normal myocardium. Selective stimulation of different types of adrenoceptor has differing electrophysiological effects. Beta 1-adrenoceptors increase contraction and calcium current, and shorten action potential duration (APD) by increasing potassium conductance. Beta 2-adrenoceptors do not increase calcium entry, but shorten APD by stimulating electrogenic Na/K pumping, alpha-adrenoceptors prolong contractions and lengthen APD. It is suggested that the tachycardia, extrasystoles and shortening of APD occurring in response to adrenergic stimuli and hypoxia, are accessory factors, not primary causes, in the development of arrhythmias, and constitute a danger when there is an appropriate anatomical substrate for re-entry. Serious arrhythmias are of multifactorial origin, of which "calcium overload" is but one, not proven to be a frequent one.

  10. Pediatric cardiac postoperative care

    Directory of Open Access Journals (Sweden)

    Auler Jr. José Otávio Costa

    2002-01-01

    Full Text Available The Heart Institute of the University of São Paulo, Medical School is a referral center for the treatment of congenital heart diseases of neonates and infants. In the recent years, the excellent surgical results obtained in our institution may be in part due to modern anesthetic care and to postoperative care based on well-structured protocols. The purpose of this article is to review unique aspects of neonate cardiovascular physiology, the impact of extracorporeal circulation on postoperative evolution, and the prescription for pharmacological support of acute cardiac dysfunction based on our cardiac unit protocols. The main causes of low cardiac output after surgical correction of heart congenital disease are reviewed, and methods of treatment and support are proposed as derived from the relevant literature and our protocols.

  11. The cardiac anxiety questionnaire: cross-validation among cardiac inpatients

    NARCIS (Netherlands)

    Beek, M.H. van; Oude Voshaar, R.C.; Deelen, F.M. van; Balkom, A.J. van; Pop, G.A.; Speckens, A.E.

    2012-01-01

    OBJECTIVE: General anxiety symptoms are common in patients with cardiac disease and considered to have an adverse effect on cardiac prognosis. The role of specific cardiac anxiety, however, is still unknown. The aim of this study is to examine the factor structure, reliability, and validity of the D

  12. THE CARDIAC ANXIETY QUESTIONNAIRE : CROSS-VALIDATION AMONG CARDIAC INPATIENTS

    NARCIS (Netherlands)

    van Beek, M. H. C. T.; Voshaar, R. C. Oude; van Deelen, F. M.; van Balkom, A. J. L. M.; Pop, G.; Speckens, A. E. M.

    2012-01-01

    Objective: General anxiety symptoms are common in patients with cardiac disease and considered to have an adverse effect on cardiac prognosis. The role of specific cardiac anxiety, however, is still unknown. The aim of this study is to examine the factor structure, reliability, and validity of the D

  13. Electrophysiological effects of Chinese medicine Shen song Yang xin (SSYX) on Chinese miniature swine heart and isolated guinea pig ventricular myocytes

    Institute of Scientific and Technical Information of China (English)

    FENG Li; GONG Jing; JIN Zhen-yi; LI Ning; SUN Li-ping; WU Yi-ling; PU Jie-lin

    2009-01-01

    Background Shen song Yang xin (SSYX) is a compound of Chinese medicine with the effect of increasing heart rate (HR). This study aimed to evaluate its electrophysiological properties at heart and cellular levels. Methods The Chinese miniature swines were randomly assigned to two groups, administered with SSYX or placebo for 4 weeks (n=8 per group). Cardiac electrophysiological study (EPS) was performed before and after drug administration. The guinea pig ventricular myocytes were enzymatically isolated and whole cell voltage-clamp technique was used to evaluate the effect of SSYX on cardiac action potential (AP). Results SSYX treatment accelerated the HR from (141.8±36.0) beats per minute to (163.0±38.0) beats per minute (P=0.013) without changing the other parameters in surface electrocardiogram. After blockage of the autonomic nervous system with metoprolol and atropin, SSYX had no effect on intrinsic HR (IHR), but decreased corrected sinus node recovery time (CSNRT) and sinus atrium conducting time (SACT). Intra cardiac EPS showed that SSYX significantly decreased the A-H and A-V intervals as well as shortened the atrial (A), atrioventricular node (AVN) and ventricular (V) effective refractory period (ERP). In isolated guinea pig ventricular myocytes, the most obvious effect of SSYX on action potential was a shortening of the action potential duration (APD) without change in shape of action potential. The shortening rates of APD30, APD50 and APDgo were 19.5%, 17.8% and 15.3%, respectively. The resting potential (Em) and the interval between the end of APD3o and APD9o did not significantly change.Conclusions The present study demonstrates that SSYX increases the HR and enhances the conducting capacity of the heart in the condition of the intact autonomic nervous system. SSYX homogenously decreases the ERP of the heart and shortens the APD of the myocytes, suggesting its antiarrhythmic effect without proarrhythmia.

  14. Giant Cardiac Cavernous Hemangioma.

    Science.gov (United States)

    Unger, Eric; Costic, Joseph; Laub, Glenn

    2015-07-01

    We report the case of an asymptomatic giant cardiac cavernous hemangioma in a 71-year-old man. The intracardiac mass was discovered incidentally during surveillance for his prostate cancer; however, the patient initially declined intervention. On presentation to our institution 7 years later, the lesion had enlarged significantly, and the patient consented to excision. At surgery, an 8 × 6.5 × 4.8 cm intracardiac mass located on the inferior heart border was excised with an intact capsule through a median sternotomy approach. The patient had an uneventful postoperative course. We discuss the diagnostic workup, treatment, and characteristics of this rare cardiac tumor. PMID:26140782

  15. The Multi-Domain Fibroblast/Myocyte Coupling in the Cardiac Tissue: A Theoretical Study.

    Science.gov (United States)

    Greisas, Ariel; Zlochiver, Sharon

    2016-09-01

    Cardiac fibroblast proliferation and concomitant collagenous matrix accumulation (fibrosis) develop during multiple cardiac pathologies. Recent studies have demonstrated direct electrical coupling between myocytes and fibroblasts in vitro, and assessed the electrophysiological implications of such coupling. However, in the living tissues, such coupling has not been demonstrated, and only indirect coupling via the extracellular space is likely to exist. In this study we employed a multi-domain model to assess the modulation of the cardiac electrophysiological properties by neighboring fibroblasts assuming only indirect coupling. Numerical simulations in 1D and 2D human atrial models showed that extracellular coupling sustains a significant impact on conduction velocity (CV) and a less significant effect on the action potential duration. Both CV and the slope of the CV restitution increased with increasing fibroblast density. This effect was more substantial for lower extracellular conductance. In 2D, spiral waves exhibited reduced frequency with increasing fibroblast density, and the propensity of wavebreaks and complex dynamics at high pacing rates significantly increased. PMID:27150222

  16. Perioperative management of cardiac disease.

    Science.gov (United States)

    Aresti, N A; Malik, A A; Ihsan, K M; Aftab, S M E; Khan, W S

    2014-01-01

    Pre-existing cardiac disease contributes significantly to morbidity and mortality amongst patients undergoing non cardiac surgery. Patients with pre-existing cardiac disease or with risk factors for it, have as much as a 3.9% risk of suffering a major perioperative cardiac event (Lee et al 1999, Devereaux 2005). Furthermore, the incidence of perioperative myocardial infarction (MI) is increased 10 to 50 fold in patients with previous coronary events (Jassal 2008).

  17. The tarsal taste of honey bees: behavioral and electrophysiological analyses

    Directory of Open Access Journals (Sweden)

    Maria Gabriela eDe Brito Sanchez

    2014-02-01

    Full Text Available Taste plays a crucial role in the life of honey bees as their survival depends on the collection and intake of nectar and pollen, and other natural products. Here we studied the tarsal taste of honey bees through a series of behavioral and electrophysiological analyses. We characterized responsiveness to various sweet, salty and bitter tastants delivered to gustatory sensilla of the fore tarsi. Behavioral experiments showed that stimulation of opposite fore tarsi with sucrose and bitter substances or water yielded different outcomes depending on the stimulation sequence. When sucrose was applied first, thereby eliciting proboscis extension, no bitter substance could induce proboscis retraction, thus suggesting that the primacy of sucrose stimulation induced a central excitatory state. When bitter substances or water were applied first, sucrose stimulation could still elicit proboscis extension but to a lower level, thus suggesting central inhibition based on contradictory gustatory input on opposite tarsi. Electrophysiological experiments showed that receptor cells in the gustatory sensilla of the tarsomeres are highly sensitive to saline solutions at low concentrations. No evidence for receptors responding specifically to sucrose or to bitter substances was found in these sensilla. Receptor cells in the gustatory sensilla of the claws are highly sensitive to sucrose. Although bees do not possess dedicated bitter-taste receptors on the tarsi, indirect bitter detection is possible because bitter tastes inhibit sucrose receptor cells of the claws when mixed with sucrose solution. By combining behavioral and electrophysiological approaches, these results provide the first integrative study on tarsal taste detection in the honey bee.

  18. Functional cardiomyocytes derived from Isl1 cardiac progenitors via Bmp4 stimulation.

    Directory of Open Access Journals (Sweden)

    Esra Cagavi

    Full Text Available As heart failure due to myocardial infarction remains a leading cause of morbidity worldwide, cell-based cardiac regenerative therapy using cardiac progenitor cells (CPCs could provide a potential treatment for the repair of injured myocardium. As adult CPCs may have limitations regarding tissue accessibility and proliferative ability, CPCs derived from embryonic stem cells (ESCs could serve as an unlimited source of cells with high proliferative ability. As one of the CPCs that can be derived from embryonic stem cells, Isl1 expressing cardiac progenitor cells (Isl1-CPCs may serve as a valuable source of cells for cardiac repair due to their high cardiac differentiation potential and authentic cardiac origin. In order to generate an unlimited number of Isl1-CPCs, we used a previously established an ESC line that allows for isolation of Isl1-CPCs by green fluorescent protein (GFP expression that is directed by the mef2c gene, specifically expressed in the Isl1 domain of the anterior heart field. To improve the efficiency of cardiac differentiation of Isl1-CPCs, we studied the role of Bmp4 in cardiogenesis of Isl1-CPCs. We show an inductive role of Bmp directly on cardiac progenitors and its enhancement on early cardiac differentiation of CPCs. Upon induction of Bmp4 to Isl1-CPCs during differentiation, the cTnT+ cardiomyocyte population was enhanced 2.8±0.4 fold for Bmp4 treated CPC cultures compared to that detected for vehicle treated cultures. Both Bmp4 treated and untreated cardiomyocytes exhibit proper electrophysiological and calcium signaling properties. In addition, we observed a significant increase in Tbx5 and Tbx20 expression in differentiation cultures treated with Bmp4 compared to the untreated control, suggesting a link between Bmp4 and Tbx genes which may contribute to the enhanced cardiac differentiation in Bmp4 treated cultures. Collectively these findings suggest a cardiomyogenic role for Bmp4 directly on a pure population of

  19. Dose-Escalation Study for Cardiac Radiosurgery in a Porcine Model

    Energy Technology Data Exchange (ETDEWEB)

    Blanck, Oliver, E-mail: oliver.blanck@uksh.de [Department of Radiation Oncology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); CyberKnife Center Northern Germany, Guestrow (Germany); Bode, Frank [Medical Department II, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Gebhard, Maximilian [Institute of Pathology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Hunold, Peter [Department of Radiology and Nuclear Medicine, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Brandt, Sebastian [Department of Anaesthesiology and Intensive Care Medicine, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Bruder, Ralf [Institute for Robotics and Cognitive Systems, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Grossherr, Martin [Department of Anaesthesiology and Intensive Care Medicine, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Vonthein, Reinhard [Institute of Medical Biometry and Statistics, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Rades, Dirk [Department of Radiation Oncology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Dunst, Juergen [Department of Radiation Oncology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); University Copenhagen (Denmark)

    2014-07-01

    Purpose: To perform a proof-of-principle dose-escalation study to radiosurgically induce scarring in cardiac muscle tissue to block veno-atrial electrical connections at the pulmonary vein antrum, similar to catheter ablation. Methods and Materials: Nine mini-pigs underwent pretreatment magnetic resonance imaging (MRI) evaluation of heart function and electrophysiology assessment by catheter measurements in the right superior pulmonary vein (RSPV). Immediately after examination, radiosurgery with randomized single-fraction doses of 0 and 17.5-35 Gy in 2.5-Gy steps were delivered to the RSPV antrum (target volume 5-8 cm{sup 3}). MRI and electrophysiology were repeated 6 months after therapy, followed by histopathologic examination. Results: Transmural scarring of cardiac muscle tissue was noted with doses ≥32.5 Gy. However, complete circumferential scarring of the RSPV was not achieved. Logistic regressions showed that extent and intensity of fibrosis significantly increased with dose. The 50% effective dose for intense fibrosis was 31.3 Gy (odds ratio 2.47/Gy, P<.01). Heart function was not affected, as verified by MRI and electrocardiogram evaluation. Adjacent critical structures were not damaged, as verified by pathology, demonstrating the short-term safety of small-volume cardiac radiosurgery with doses up to 35 Gy. Conclusions: Radiosurgery with doses >32.5 Gy in the healthy pig heart can induce circumscribed scars at the RSPV antrum noninvasively, mimicking the effect of catheter ablation. In our study we established a significant dose-response relationship for cardiac radiosurgery. The long-term effects and toxicity of such high radiation doses need further investigation in the pursuit of cardiac radiosurgery for noninvasive treatment of atrial fibrillation.

  20. The cardiac malpositions.

    Science.gov (United States)

    Perloff, Joseph K

    2011-11-01

    Dextrocardia was known in the 17th century and was 1 of the first congenital malformations of the heart to be recognized. Fifty years elapsed before Matthew Baillie published his account of complete transposition in a human of the thoracic and abdominal viscera to the opposite side from what is natural. In 1858, Thomas Peacock stated that "the heart may be congenitally misplaced in various ways, occupying either an unusual position within the thorax, or being situated external to that cavity." In 1915, Maude Abbott described ectopia cordis, and Richard Paltauf's remarkable illustrations distinguished the various types of dextrocardia. In 1928, the first useful classification of the cardiac malpositions was proposed, and in 1966, Elliott et al's radiologic classification set the stage for clinical recognition. The first section of this review deals with the 3 basic cardiac malpositions in the presence of bilateral asymmetry. The second section deals with cardiac malpositions in the presence of bilateral left-sidedness or right-sidedness. Previous publications on cardiac malpositions are replete with an arcane vocabulary that confounds rather than clarifies. Even if the terms themselves are understood, inherent complexity weighs against clarity. This review was designed as a guided tour of an unfamiliar subject.

  1. Cardiac effects of vasopressin.

    Science.gov (United States)

    Pelletier, Jean-Sébastien; Dicken, Bryan; Bigam, David; Cheung, Po-Yin

    2014-07-01

    Vasopressin is an essential hormone involved in the maintenance of cardiovascular homeostasis. It has been in use therapeutically for many decades, with an emphasis on its vasoconstrictive and antidiuretic properties. However, this hormone has a ubiquitous influence and has specific effects on the heart. Although difficult to separate from its powerful vascular effects in the clinical setting, a better understanding of vasopressin's direct cardiac effects could lead to its more effective clinical use for a variety of shock states by maximizing its therapeutic benefit. The cardiac-specific effects of vasopressin are complex and require further elucidation. Complicating our understanding include the various receptors and secondary messengers involved in vasopressin's effects, which may lead to various results based on differing doses and varying environmental conditions. Thus, there have been contradictory reports on vasopressin's action on the coronary vasculature and on its effect on inotropy. However, beneficial results have been found and warrant further study to expand the potential therapeutic role of vasopressin. This review outlines the effect of vasopressin on the coronary vasculature, cardiac contractility, and on hypertrophy and cardioprotection. These cardiac-specific effects of vasopressin represent an interesting area for further study for potentially important therapeutic benefits. PMID:24621650

  2. Cardiac potassium channel subtypes

    DEFF Research Database (Denmark)

    Schmitt, Nicole; Grunnet, Morten; Olesen, Søren-Peter

    2014-01-01

    About 10 distinct potassium channels in the heart are involved in shaping the action potential. Some of the K(+) channels are primarily responsible for early repolarization, whereas others drive late repolarization and still others are open throughout the cardiac cycle. Three main K(+) channels...

  3. Cardiac pacemaker power sources

    International Nuclear Information System (INIS)

    A review of chemical and radioisotope batteries used in cardiac pacemakers is presented. The battery systems are examined in terms of longevity, reliability, cost, size and shape, energy density, weight, internal resistance versus time, end-of-life voltage, chemical compatibility, and potential failure mechanisms

  4. Finding the rhythm of sudden cardiac death: new opportunities using induced pluripotent stem cell-derived cardiomyocytes.

    Science.gov (United States)

    Sallam, Karim; Li, Yingxin; Sager, Philip T; Houser, Steven R; Wu, Joseph C

    2015-06-01

    Sudden cardiac death is a common cause of death in patients with structural heart disease, genetic mutations, or acquired disorders affecting cardiac ion channels. A wide range of platforms exist to model and study disorders associated with sudden cardiac death. Human clinical studies are cumbersome and are thwarted by the extent of investigation that can be performed on human subjects. Animal models are limited by their degree of homology to human cardiac electrophysiology, including ion channel expression. Most commonly used cellular models are cellular transfection models, which are able to mimic the expression of a single-ion channel offering incomplete insight into changes of the action potential profile. Induced pluripotent stem cell-derived cardiomyocytes resemble, but are not identical, adult human cardiomyocytes and provide a new platform for studying arrhythmic disorders leading to sudden cardiac death. A variety of platforms exist to phenotype cellular models, including conventional and automated patch clamp, multielectrode array, and computational modeling. Induced pluripotent stem cell-derived cardiomyocytes have been used to study long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, hypertrophic cardiomyopathy, and other hereditary cardiac disorders. Although induced pluripotent stem cell-derived cardiomyocytes are distinct from adult cardiomyocytes, they provide a robust platform to advance the science and clinical care of sudden cardiac death. PMID:26044252

  5. Complex structure of electrophysiological gradients emerging during long-duration ventricular fibrillation in the canine heart.

    Science.gov (United States)

    Venable, Paul W; Taylor, Tyson G; Shibayama, Junko; Warren, Mark; Zaitsev, Alexey V

    2010-11-01

    Long-duration ventricular fibrillation (LDVF) in the globally ischemic heart is a common setting of cardiac arrest. Electrical heterogeneities during LDVF may affect outcomes of defibrillation and resuscitation. Previous studies in large mammalian hearts have investigated the role of Purkinje fibers and electrophysiological gradients between the endocardium (Endo) and epicardium (Epi). Much less is known about gradients between the right ventricle (RV) and left ventricle (LV) and within each chamber during LDVF. We studied the transmural distribution of the VF activation rate (VFR) in the RV and LV and at the junction of RV, LV, and septum (Sep) during LDVF using plunge needle electrodes in opened-chest dogs. We also used optical mapping to analyze the Epi distribution of VFR, action potential duration (APD), and diastolic interval (DI) during LDVF in the RV and LV of isolated hearts. Transmural VFR gradients developed in both the RV and LV, with a faster VFR in Endo. Concurrently, large VFR gradients developed in Epi, with the fastest VFR in the RV-Sep junction, intermediate in the RV, and slowest in the LV. Optical mapping revealed a progressively increasing VFR dispersion within both the LV and RV, with a mosaic presence of fully inexcitable areas after 4-8 min of LDVF. The transmural, interchamber, and intrachamber VFR heterogeneities were of similar magnitude. In both chambers, the inverse of VFR was highly correlated with DI, but not APD, at all time points of LDVF. We conclude that the complex VFR gradients during LDVF in the canine heart cannot be explained solely by the distribution of Purkinje fibers and are related to regional differences in the electrical depression secondary to LDVF.

  6. Electrophysiological, vasoactive, and gastromodulatory effects of stevia in healthy Wistar rats.

    Science.gov (United States)

    Yesmine, Saquiba; Connolly, Kylie; Hill, Nicholas; Coulson, Fiona R; Fenning, Andrew S

    2013-07-01

    Antihypertensive and antidiabetic effects of stevia, Stevia rebaudiana (Asteraceae), have been demonstrated in several human and animal models. The current study aims to define stevia's role in modifying the electrophysiological and mechanical properties of cardiomyocytes, blood vessels, and gastrointestinal smooth muscle. Tissues from thoracic aorta, mesenteric arteries, ileum, and left ventricular papillary muscles were excised from 8-week-old healthy Wistar rats. The effects of stevia (1 × 10-9 M to 1 × 10-4 M) were measured on these tissues. Stevia's effects in the presence of verapamil, 4-AP, and L-NAME were also assessed. In cardiomyocytes, stevia attenuated the force of contraction, decreased the average peak amplitude, and shortened the repolarisation phase of action potential - repolarisation phase of action potential20 by 25 %, repolarisation phase of action potential50 by 34 %, and repolarisation phase of action potential90 by 36 %. Stevia caused relaxation of aortic tissues which was significantly potentiated in the presence of verapamil. In mesenteric arteries, incubation with L-NAME failed to block stevia-induced relaxation indicating the mechanism of action may not be fully via nitric oxide-dependent pathways. Stevia concentration-dependently reduced electrical field stimulated and carbachol-induced contractions in the isolated ileum. This study is the first to show the effectiveness of stevia in reducing cardiac action potential duration at 20 %, 50 %, and 90 % of repolarisation. Stevia also showed beneficial modulatory effects on cardiovascular and gastrointestinal tissues via calcium channel antagonism, activation of the M2 muscarinic receptor function, and enhanced nitric oxide release.

  7. mRNA expression levels in failing human hearts predict cellular electrophysiological remodeling: a population-based simulation study.

    Directory of Open Access Journals (Sweden)

    John Walmsley

    Full Text Available Differences in mRNA expression levels have been observed in failing versus non-failing human hearts for several membrane channel proteins and accessory subunits. These differences may play a causal role in electrophysiological changes observed in human heart failure and atrial fibrillation, such as action potential (AP prolongation, increased AP triangulation, decreased intracellular calcium transient (CaT magnitude and decreased CaT triangulation. Our goal is to investigate whether the information contained in mRNA measurements can be used to predict cardiac electrophysiological remodeling in heart failure using computational modeling. Using mRNA data recently obtained from failing and non-failing human hearts, we construct failing and non-failing cell populations incorporating natural variability and up/down regulation of channel conductivities. Six biomarkers are calculated for each cell in each population, at cycle lengths between 1500 ms and 300 ms. Regression analysis is performed to determine which ion channels drive biomarker variability in failing versus non-failing cardiomyocytes. Our models suggest that reported mRNA expression changes are consistent with AP prolongation, increased AP triangulation, increased CaT duration, decreased CaT triangulation and amplitude, and increased delay between AP and CaT upstrokes in the failing population. Regression analysis reveals that changes in AP biomarkers are driven primarily by reduction in I[Formula: see text], and changes in CaT biomarkers are driven predominantly by reduction in I(Kr and SERCA. In particular, the role of I(CaL is pacing rate dependent. Additionally, alternans developed at fast pacing rates for both failing and non-failing cardiomyocytes, but the underlying mechanisms are different in control and heart failure.

  8. SYMMETRY AS A PRINCIPLE OF ELECTROPHYSIOLOGICAL PROCESSES COGNITION

    Directory of Open Access Journals (Sweden)

    N.V. Dmitrieva

    2012-09-01

    Full Text Available It is considering the problem of general principals of symmetry for the definition of the connections of oscillation processes in an organism. The symmetry as the condition of a system organization determines the capacity of evaluating of its accuracy and integrity. The methods of cognitive graphic and artificial intelligence algorithms are the power tools for a system analysis of physiological processes. For a long-term the polyparametric methodology of the system analysis of electrophysiological processes with modeling of them on the basis of the fractal geometry and cognitive graphic was developed. The gist of this methodology consists in a parameterization of electrophysiological processes, construction of the geometric model with the uniform set of parameters and using general principals of symmetry and the algorithms of artificial intelligence systems to analyze multi-dimension physiological data. On this base the methods for the system analysis of electrocardiogram, electroreovasogram, electroencephalogram, polyparametric method for an evaluation of human functional state and others were developed.

  9. Modern Electrophysiological Methods for Brain-Computer Interfaces

    Directory of Open Access Journals (Sweden)

    Rolando Grave de Peralta Menendez

    2007-01-01

    Full Text Available Modern electrophysiological studies in animals show that the spectrum of neural oscillations encoding relevant information is broader than previously thought and that many diverse areas are engaged for very simple tasks. However, EEG-based brain-computer interfaces (BCI still employ as control modality relatively slow brain rhythms or features derived from preselected frequencies and scalp locations. Here, we describe the strategy and the algorithms we have developed for the analysis of electrophysiological data and demonstrate their capacity to lead to faster accurate decisions based on linear classifiers. To illustrate this strategy, we analyzed two typical BCI tasks. (1 Mu-rhythm control of a cursor movement by a paraplegic patient. For this data, we show that although the patient received extensive training in mu-rhythm control, valuable information about movement imagination is present on the untrained high-frequency rhythms. This is the first demonstration of the importance of high-frequency rhythms in imagined limb movements. (2 Self-paced finger tapping task in three healthy subjects including the data set used in the BCI-2003 competition. We show that by selecting electrodes and frequency ranges based on their discriminative power, the classification rates can be systematically improved with respect to results published thus far.

  10. Electrophysiologic Effects of Propafenone on Ischemic Ventricular Tachyarrhythmias

    Institute of Scientific and Technical Information of China (English)

    Liu Musheng; Ma Yanfeng; Guo Zhibin

    2006-01-01

    Objectives To observe the electrophysiologic effects of propafenone (Prop) on ischemic ventricular tachyarrhythmias. Methods A canine ischemic ventricular tachyarrhythmia model was established in open-chest dogs subjected to programmed electrical stimulation (PES) on 5~8 days after acute myocardial infarction. The electrophysiologic effects of propafenone were observed in the model. Results Propafenone distinctly lengthened the QTc interval (P> 0.01) and effective refractory period (ERP) of normal and ischemic ventricular myocardium (NERP and IERP) respectively (P > 0.01), decreased the dispersion of ERP in ischemic myocardium and in left ventricle (P > 0.01), and increased the diastolic excitability threshold of normal and ischemic ventricular myocardium remarkably (P > 0.01). Propafenone effectively prevented PES-induced ventricular tachycardia (VT) or ventricular fibrillation (VF)(P > 0.01) and ischemia-induced VT/VF (P > 0.05).Conclusions The results indicated that the canine model produced by our methods is a worthy and reliable one, propafenone may be effective in preventing the onset of VT/VF after myocardial ischemic damage in dogs, and deserve further attention as an antifibrillatory agent.

  11. How do astrocytes shape synaptic transmission? Insights from electrophysiology

    Directory of Open Access Journals (Sweden)

    Glenn eDallérac

    2013-10-01

    Full Text Available A major breakthrough in neuroscience has been the realization in the last decades that the dogmatic view of astroglial cells as being merely fostering and buffering elements of the nervous system is simplistic. A wealth of investigations now shows that astrocytes actually participate in the control of synaptic transmission in an active manner. This was first hinted by the intimate contacts glial processes make with neurons, particularly at the synaptic level, and evidenced using electrophysiological and calcium imaging techniques. Calcium imaging has provided critical evidence demonstrating that astrocytic regulation of synaptic efficacy is not a passive phenomenon. However, given that cellular activation is not only represented by calcium signaling, it is also crucial to assess concomitant mechanisms. We and others have used electrophysiological techniques to simultaneously record neuronal and astrocytic activity, thus enabling the study of multiple ionic currents and in depth investigation of neuro-glial dialogues. In the current review, we focus on the input such approach has provided in the understanding of astrocyte-neuron interactions underlying control of synaptic efficacy.

  12. Electrophysiologic abnormalities of children with ostium secundum atrial septal defect.

    Science.gov (United States)

    Ruschhaupt, D G; Khoury, L; Thilenius, O G; Replogle, R L; Arcilla, R A

    1984-06-01

    Sinus node (SN) and atrioventricular node (AVN) function were evaluated in 49 patients with secundum type atrial septal defect (ASD). Automaticity and conduction system function were assessed by intracardiac recording of the AH and HV intervals at rest, corrected SN recovery time, sinoatrial conduction time, AVN refractory period and the ability of the AVN to conduct rapidly paced atrial beats to the ventricles. Electrophysiologic abnormalities were found in 41% of the 34 patients who were studied before surgery. However, no preoperative abnormalities were present in children younger than 2.5 years. If only children older than 2.5 years were analyzed, the incidence of conduction abnormalities was similar for the patients studied before operation (62%) and those studied after operation (71%). The size and ejection fractions of the right and left ventricles, the magnitude of shunt flow and the size of the ASD did not differ between the patients with and those without electrophysiologic abnormalities. AVN dysfunction was present in 40% of the patients who were studied after surgical repair. While this frequency was more than twice the preoperative incidence of AVN dysfunction, it was not statistically significant. The data suggest that patient age is the major factor that influences the presence of conduction system dysfunction in patients with ASD.

  13. Electrophysiological correlates of reading the single- and interactive-mind

    Directory of Open Access Journals (Sweden)

    Yi-Wen eWang

    2011-07-01

    Full Text Available Understanding minds is the cognitive basis of successful social interaction. In everyday life, human mental activity often happens at the moment of social interaction among two or multiple persons instead of only one person. Understanding the interactive mind of two- or multi-person is more complex and higher than understanding the single-person mind in the hierarchical structure of theory-of-mind. Understanding the interactive mind maybe differentiate from understanding the single mind. In order to examine the dissociative electrophysiological correlates of reading the single mind and reading the interactive mind, the 64 channels event-related potentials (ERP were recorded while 16 normal adults were observing three kinds of Chinese idioms depicted physical scenes, one-person with mental activity and two- or multi-person with mental interaction. After the equivalent N400, in the 500- to 700-ms epoch, the mean amplitudes of late positive component (LPC over frontal for reading the single mind and reading the interactive mind were significantly more positive than for physical representation, while there was no difference between the former two. In the 700-to 800-ms epoch, the mean amplitudes of LPC over frontal-central for reading the interactive mind were more positive than for reading the single mind and physical representation, while there was no difference between the latter two. The present study provides electrophysiological signature of the dissociations between reading the single mind and reading the interactive mind.

  14. Clinical and electrophysiological study of chronic inflammatory demyelinating polyneuropathy

    Institute of Scientific and Technical Information of China (English)

    秦绍森; 玛依努尔; 王湘

    2001-01-01

    Objective To investigate the clinical and electrophysiological features of chronic inflammatory demyelinating polyneuropathy (CIDP) . Methods The clinical symptoms and signs of 11 patients with CIDP were studied, motor conduction velocity( MCV), sensory con-duction velocity (SCV) and Electromyography (EMG) were also respectively carried out on 54 motor nerves, 28 sensory nerves and 21 musclesof these 11 cases. The amplitudes of compound muscle action potential(CAMP) obtained from distal and proximal ends were compared to as-certain the presence of conduction block (CB) by stimulating the segments starting from the distal ends. Results More than 3 nerves werefound involved in 10 out of 11 cases, slow MCV were found in 52%, prolongation of the distal latency in 64%, reduction of the amplitudes ofCAMP in 68%, CB in 26%, slow SCV in 85. 7%. EMG revealed neurogenic damage in 81%. Conclusion CIDP is a peripheral de- myelinating neuropathy involving not only the prox imal and distal segments but also the sensory and motor nerves. If there were no conditionsto perform nerve biopsy, testing of protein in CSF and electrophysiology mightbe of important diagnostic value for CIDP.

  15. Automatic fitting of spiking neuron models to electrophysiological recordings

    Directory of Open Access Journals (Sweden)

    Cyrille Rossant

    2010-03-01

    Full Text Available Spiking models can accurately predict the spike trains produced by cortical neurons in response to somatically injected currents. Since the specific characteristics of the model depend on the neuron, a computational method is required to fit models to electrophysiological recordings. The fitting procedure can be very time consuming both in terms of computer simulations and in terms of code writing. We present algorithms to fit spiking models to electrophysiological data (time-varying input and spike trains that can run in parallel on graphics processing units (GPUs. The model fitting library is interfaced with Brian, a neural network simulator in Python. If a GPU is present it uses just-in-time compilation to translate model equations into optimized code. Arbitrary models can then be defined at script level and run on the graphics card. This tool can be used to obtain empirically validated spiking models of neurons in various systems. We demonstrate its use on public data from the INCF Quantitative Single-Neuron Modeling 2009 competition by comparing the performance of a number of neuron spiking models.

  16. Cardiac fusion and complex congenital cardiac defects in thoracopagus twins: diagnostic value of cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Hyun Woo [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of); Park, Jeong-Jun [University of Ulsan College of Medicine, Asan Medical Center, Department of Pediatric Cardiac Surgery, Seoul (Korea, Republic of); Kim, Ellen Ai-Rhan [University of Ulsan College of Medicine, Asan Medical Center, Division of Neonatology, Department of Pediatrics, Seoul (Korea, Republic of); Won, Hye-Sung [University of Ulsan College of Medicine, Asan Medical Center, Department of Obstetrics and Gynecology, Seoul (Korea, Republic of)

    2014-09-15

    Most thoracopagus twins present with cardiac fusion and associated congenital cardiac defects, and assessment of this anatomy is of critical importance in determining patient care and outcome. Cardiac CT with electrocardiographic triggering provides an accurate and quick morphological assessment of both intracardiac and extracardiac structures in newborns, making it the best imaging modality to assess thoracopagus twins during the neonatal period. In this case report, we highlight the diagnostic value of cardiac CT in thoracopagus twins with an interatrial channel and complex congenital cardiac defects. (orig.)

  17. Electrophysiological Auditory Responses and Language Development in Infants with Periventricular Leukomalacia

    Science.gov (United States)

    Avecilla-Ramirez, G. N.; Ruiz-Correa, S.; Marroquin, J. L.; Harmony, T.; Alba, A.; Mendoza-Montoya, O.

    2011-01-01

    This study presents evidence suggesting that electrophysiological responses to language-related auditory stimuli recorded at 46 weeks postconceptional age (PCA) are associated with language development, particularly in infants with periventricular leukomalacia (PVL). In order to investigate this hypothesis, electrophysiological responses to a set…

  18. The assessment of visually impaired persons working capacities using electrophysiological and ophthalmic ergonomics methods

    Directory of Open Access Journals (Sweden)

    M. I. Razumovsky

    2014-07-01

    Full Text Available Aim was to analyze working capacities of visually impaired persons by means of complex electrophysiological and ophthalmic ergonomics eye examination.Materials and methods. Standard clinical ophthalmologic examination (visual acuity measurement, refractometry, biomicroscopy, ophthalmoscopy as well as electrophysiological (electrooculography, electrical sensitivity of the eye, critical flicker fusion frequency and ophthalmic ergonomics tests (accommodation measurement, professional testing using automated system «Proftest-1» were performed.Results. Complex electrophysiological and ophthalmic ergonomics tests were performed in 20 visually impaired persons. Their results revealed direct correlation between electrophysiological and ophthalmic ergonomics indices.Conclusion. Working capacities of visually impaired persons can be assessed reliably using complex electrophysiological and ophthalmic ergonomics eye examination only.

  19. The assessment of visually impaired persons working capacities using electrophysiological and ophthalmic ergonomics methods

    Directory of Open Access Journals (Sweden)

    M. I. Razumovsky

    2014-01-01

    Full Text Available Aim was to analyze working capacities of visually impaired persons by means of complex electrophysiological and ophthalmic ergonomics eye examination.Materials and methods. Standard clinical ophthalmologic examination (visual acuity measurement, refractometry, biomicroscopy, ophthalmoscopy as well as electrophysiological (electrooculography, electrical sensitivity of the eye, critical flicker fusion frequency and ophthalmic ergonomics tests (accommodation measurement, professional testing using automated system «Proftest-1» were performed.Results. Complex electrophysiological and ophthalmic ergonomics tests were performed in 20 visually impaired persons. Their results revealed direct correlation between electrophysiological and ophthalmic ergonomics indices.Conclusion. Working capacities of visually impaired persons can be assessed reliably using complex electrophysiological and ophthalmic ergonomics eye examination only.

  20. Sudden Cardiac Death

    Directory of Open Access Journals (Sweden)

    Yipsy María Gutiérrez Báez

    2015-09-01

    Full Text Available Since the second half of the twentieth century, dying suddenly due to heart-related problems has become the main health issue in all countries where infectious diseases are not prevalent. Sudden death from cardiac causes is an important global health problem. Major databases were searched for the leading causes of sudden cardiac death. It has been demonstrated that there is a group of hereditary diseases with structural alterations or without apparent organic cause that explains many cases of sudden death in young people, whether related or not to physical exertion. Certain population groups are at higher risk for this disease. They are relatively easy to identify and can be the target of primary prevention measures.

  1. Inherited cardiac disease

    Directory of Open Access Journals (Sweden)

    Philippe Charron

    2012-06-01

    Full Text Available Major advances have been achieved over the two last decades in the field of genetic cardiovascular diseases, not only through increased recognition and understanding of underlying molecular defects but also through rapid translation of knowledge into clinical practice. Genetic counseling and organization of cardiac family screening has become part of the medical management of these diseases, and these should be performed systematically unless an acquired cause has been diagnosed...

  2. Cardiac Tissue Engineering

    OpenAIRE

    MILICA RADISIC; GORDANA VUNJAK-NOVAKOVIC

    2009-01-01

    We hypothesized that clinically sized (1-5 mm thick),compact cardiac constructs containing physiologically high density of viable cells (~108 cells/cm3) can be engineered in vitro by using biomimetic culture systems capable of providing oxygen transport and electrical stimulation, designed to mimic those in native heart. This hypothesis was tested by culturing rat heart cells on polymer scaffolds, either with perfusion of culture medium (physiologic interstitial velocity, supplementation of p...

  3. Cardiac developmental toxicity

    OpenAIRE

    Mahler, Gretchen J.; Jonathan T Butcher

    2011-01-01

    Congenital heart disease is a highly prevalent problem with mostly unknown origins. Many cases of CHD likely involve an environmental exposure coupled with genetic susceptibility, but practical and ethical considerations make nongenetic causes of CHD difficult to assess in humans. The development of the heart is highly conserved across all vertebrate species, making animal models an excellent option for screening potential cardiac teratogens. This review will discuss exposures known to cause ...

  4. Cardiac-Specific Overexpression of SCN5A Gene Leads to Shorter P Wave Duration and PR Interval in Transgenic Mice

    OpenAIRE

    Zhang, Teng; Yong, Sandro L.; Tian, Xiao-Li; Wang, Qing K.

    2007-01-01

    SCN5A plays a critical role in cardiac electrophysiology and its mutations, either gain- or loss-of-functions, are associated with lethal arrhythmias. In this study we investigated the effect of overexpression of SCN5A on the cardiac phenotype in a transgenic mouse model (TG-WT L10). Compared to NTG mice, heart rate, QRS duration and QT intervals remained unchanged in TG-WT mice. Moreover, no spontaneous ventricular arrhythmias were detected in TG-WT hearts. Despite these results, a mild, irr...

  5. Cardiac hybrid imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gaemperli, Oliver [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); University Hospital Zurich, Nuclear Cardiology, Cardiovascular Center, Zurich (Switzerland); Kaufmann, Philipp A. [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland)

    2014-05-15

    Hybrid cardiac single photon emission computed tomography (SPECT)/CT imaging allows combined assessment of anatomical and functional aspects of cardiac disease. In coronary artery disease (CAD), hybrid SPECT/CT imaging allows detection of coronary artery stenosis and myocardial perfusion abnormalities. The clinical value of hybrid imaging has been documented in several subsets of patients. In selected groups of patients, hybrid imaging improves the diagnostic accuracy to detect CAD compared to the single imaging techniques. Additionally, this approach facilitates functional interrogation of coronary stenoses and guidance with regard to revascularization procedures. Moreover, the anatomical information obtained from CT coronary angiography or coronary artery calcium scores (CACS) adds prognostic information over perfusion data from SPECT. The use of cardiac hybrid imaging has been favoured by the dissemination of dedicated hybrid systems and the release of dedicated image fusion software, which allow simple patient throughput for hybrid SPECT/CT studies. Further technological improvements such as more efficient detector technology to allow for low-radiation protocols, ultra-fast image acquisition and improved low-noise image reconstruction algorithms will be instrumental to further promote hybrid SPECT/CT in research and clinical practice. (orig.)

  6. Biochemical and electrophysiological characteristics of mammalian GABA receptors.

    Science.gov (United States)

    Enna, S J; Gallagher, J P

    1983-01-01

    The concept that GABA is a neurotransmitter in the mammalian CNS is supported by both electrophysiological and biochemical data. Whereas the electrophysiological studies are essential for demonstrating a specific functional response to GABA, the biochemical approach is useful for characterizing the molecular properties of this site. As a result of these studies the concept of the GABA receptor has progressed from a simple model of a single recognition site associated with a chloride channel to a more complex structure having a variety of interacting components. Thus, both electrophysiological and biochemical data support the existence of at least two pharmacologically distinct types of GABA receptors, based on the sensitivity to bicuculline. Also, anatomically, there appear to be two different types of receptors, those located postsynaptically on the soma or dendrites of a neighboring cell and those found presynaptically on GABAergic and other neurotransmitter terminals. From biochemical studies it appears that the GABA receptor may be composed of at least three distinct interacting components. One of these, the recognition site, may exist in two conformations, with one preferring agonists and the other having a higher affinity for antagonists. Ion channels may be considered a second component, with some of these regulating the passage of chloride ion, whereas others may be associated with calcium transport. The third major element of GABA receptors appears to be a benzodiazepine recognition site, although only a certain population of GABA receptors may be endowed with this property. In addition to these, the GABA receptor complex appears to contain substances that modulate the recognition site by influencing the availability of higher affinity binding proteins. It would appear therefore that changes affecting any one of these constituents can influence the characteristics of the others. While increasing the complexity of the system, this arrangement makes for a

  7. Virtual NEURON: a strategy for merged biochemical and electrophysiological modeling.

    Science.gov (United States)

    Brown, Sherry-Ann; Moraru, Ion I; Schaff, James C; Loew, Leslie M

    2011-10-01

    Because of its highly branched dendrite, the Purkinje neuron requires significant computational resources if coupled electrical and biochemical activity are to be simulated. To address this challenge, we developed a scheme for reducing the geometric complexity; while preserving the essential features of activity in both the soma and a remote dendritic spine. We merged our previously published biochemical model of calcium dynamics and lipid signaling in the Purkinje neuron, developed in the Virtual Cell modeling and simulation environment, with an electrophysiological model based on a Purkinje neuron model available in NEURON. A novel reduction method was applied to the Purkinje neuron geometry to obtain a model with fewer compartments that is tractable in Virtual Cell. Most of the dendritic tree was subject to reduction, but we retained the neuron's explicit electrical and geometric features along a specified path from spine to soma. Further, unlike previous simplification methods, the dendrites that branch off along the preserved explicit path are retained as reduced branches. We conserved axial resistivity and adjusted passive properties and active channel conductances for the reduction in surface area, and cytosolic calcium for the reduction in volume. Rallpacks are used to validate the reduction algorithm and show that it can be generalized to other complex neuronal geometries. For the Purkinje cell, we found that current injections at the soma were able to produce similar trains of action potentials and membrane potential propagation in the full and reduced models in NEURON; the reduced model produces identical spiking patterns in NEURON and Virtual Cell. Importantly, our reduced model can simulate communication between the soma and a distal spine; an alpha function applied at the spine to represent synaptic stimulation gave similar results in the full and reduced models for potential changes associated with both the spine and the soma. Finally, we combined

  8. ROLE OF ELECTROPHYSIOLOGY IN EARLY DETECTION OF HEA RING IMPAIRMENT

    Directory of Open Access Journals (Sweden)

    Sree Devi

    2013-05-01

    Full Text Available ABSTRACT: In the present study about 72 children with complai nts of hearing impairment attending the Outpatient department of Government Ear, Nose a nd Throat Hospital were taken up. These children were chosen randomly and were followed up from consultation stage till the final diagnosis after completion of all the tests. The age range of children was from 1 year to 7 years. 43 Children were males and 29 children were females. All the ch ildren attended the Government E.N.T. Hospital for evaluation and further evaluations were done at the Hearing Aid Centre. Most of the children were from poor socio-economic status (White Ration Card Holders. Average time taken for each child ranged from 60 minutes to 120 minutes since t he physiological tests have to be done for the children under sedation as they are not co-operativ e. The Aims and Objectives of this study are 1. Early detection of hearing impairment in children h as been the main aim of this study. Children of age groups, ranging from 1 – 7 years with a complaint o f hearing impairment are taken up for this study. Main emphasis being on sensori-neural hearing loss with or without speech impairment, cases of external and middle ear conditions are excluded.2. Assessment of the type and degree of hearing loss and knowing probable site of pathology by conductin g a battery of tests- PTA (pure tone audiometry, FFA(Free field Audiometry, Impedance Audiometry, OAE(otoacoustic emissions, and BERA(Brain stem Evoked Response Audiometry.3. Know ing efficacy and accuracy of Electrophysiological tests in children who are othe rwise uncooperative or cannot understand and follow the subjective tests. 4. Comparing the resul ts of Electrophysiological tests and subjective tes ts. 5. Analyzing the data in terms of gender, etiology, type of hearing loss etc. With the advent of the advanced electrophysiological tests of hearing like BERA, OAE, Electrocochleography and Auditory Steady State Response audiometry

  9. Microcomputer-based recording system for clinical electrophysiology.

    Science.gov (United States)

    Török, B

    1990-09-01

    We developed a personal computer-based system for clinical electrophysiologic measurements. The computer interfaced with a commercially available A/D converter, a low-noise isolation preamplifier, filter circuits, pattern and Ganzfeld stimulators, and a hardcopy unit. Separate programs were developed for electroretinography (ERG), pattern ERG and simultaneous visual evoked potential (VEP), flash and pattern-shift VEP, and electro-oculographic measurements. The complete control of the applied hardware (eg, stimulus control, automatic gain, and filter selection) is a common feature of the computer programs. These programs provide oscilloscopic functions, overload protection, artifact elimination, averaging, automatic peak latency and amplitude determination, baseline correction, smoothing, and digital filtering. The results can be presented on matrix, laser printers, or digital plotters. The hardware components and the features of the driver software are demonstrated on normal and pathologic signals. PMID:2276319

  10. [Electrophysiology principles of Na(+)/HCO3(-) cotransporters].

    Science.gov (United States)

    Chen, Li-Ming; Liu, Mei; Liu, Ying

    2016-06-25

    Ion channels and transporters represent two major types of pathways of transmembrane transport for ions. Distinct from ion channels which conduct passive ionic diffusion, ion transporters mediate active transport of ions. In the perspective of biochemistry, ion transporters are enzymes that catalyze the movement of ions across the plasma membrane. In the present review, we selected the Na(+)/HCO3(-) cotransporter (NBC) as an example to analyze the key biochemical and biophysical properties of ion transporters, including stoichiometry, turnover number and transport capacity. Moreover, we provided an analysis of the electrophysiological principles of NBC based on the laws of thermodynamics. Based on the thermodynamical analysis, we showed how the stoichiometry of an NBC determines the direction of its ion transport. Finally, we reviewed the methodology for experimental determination of the stoichiometry of NBC, as well as the physiological significance of the stoichiometry of NBCs in specific tissues. PMID:27350205

  11. Information Technologies for Biology Education: Computerized Electrophysiology of Plant Cells

    Directory of Open Access Journals (Sweden)

    Vilma KISNIERIENE

    2008-04-01

    Full Text Available Biology has moved from a bench-based discipline to a bioinformational science in modern times but application of computational and analytical methods of informatics in it is still a problem for many researchers and students of biology. We suggest to integrate cost effective and practical combination of the real and the virtual laboratories into the undergraduate biological science curriculum. This laboratory work illustrates passive and active electrical properties of plant cell membranes while introducing basic principles of electrophysiological recording, data acquisition and analysis. As the object for investigation in this laboratory work large cells of starry stonewort (Nitellopsis obtusa were used. The simple program for experiment control and express visualization of recorded data was developed. Experiment proposed in this paper is easy implemented with a minimum of laboratory equipment, materials and gives an experience of computerized biological experiment.

  12. Increased dopaminergic activity in socially isolated rats: an electrophysiological study

    DEFF Research Database (Denmark)

    Fabricius, Katrine; Helboe, Lone; Fink-Jensen, Anders;

    2010-01-01

    The development of animal models mimicking symptoms associated with schizophrenia has been a critical step in understanding the neurobiological mechanisms underlying the disease. Long-term social isolation from weaning in rodents, a model based on the neurodevelopmental hypothesis of schizophrenia......, has been suggested to mimic some of the deficits seen in schizophrenic patients. We confirm in the present study that socially isolated rats display an increase in both spontaneous and d-amphetamine-induced locomotor activity, as well as deficits in sensorimotor gating as assessed in a pre......-pulse inhibition paradigm. In addition, in vivo electrophysiological studies revealed changes in dopaminergic cell firing activity in the ventral tegmental area of isolated rats when compared to group-housed controls. These alterations include an increase in the number of spontaneously active dopaminergic neurons...

  13. Electrophysiologic Assessment of Auditory Training Benefits in Older Adults.

    Science.gov (United States)

    Anderson, Samira; Jenkins, Kimberly

    2015-11-01

    Older adults often exhibit speech perception deficits in difficult listening environments. At present, hearing aids or cochlear implants are the main options for therapeutic remediation; however, they only address audibility and do not compensate for central processing changes that may accompany aging and hearing loss or declines in cognitive function. It is unknown whether long-term hearing aid or cochlear implant use can restore changes in central encoding of temporal and spectral components of speech or improve cognitive function. Therefore, consideration should be given to auditory/cognitive training that targets auditory processing and cognitive declines, taking advantage of the plastic nature of the central auditory system. The demonstration of treatment efficacy is an important component of any training strategy. Electrophysiologic measures can be used to assess training-related benefits. This article will review the evidence for neuroplasticity in the auditory system and the use of evoked potentials to document treatment efficacy. PMID:27587912

  14. The sense of smell in Odonata: an electrophysiological screening.

    Science.gov (United States)

    Piersanti, Silvana; Frati, Francesca; Conti, Eric; Rebora, Manuela; Salerno, Gianandrea

    2014-11-01

    Volatile chemicals mediate a great range of intra- and interspecific signalling and information in insects. Olfaction has been widely investigated mostly in Neoptera while the knowledge of this sense in most basal insects such as Paleoptera (Odonata and Ephemeroptera) is still poor. In the present study we show the results of an electrophysiological screening on two model species, Libellula depressa (Libellulidae) and Ischnura elegans (Coenagrionidae), representatives of the two Odonata suborders Anisoptera and Zygoptera, with the aim to deep the knowledge on the sense of smell of this insect order. The antennal olfactory sensory neurons (OSNs) of these two species responded to the same 22 compounds (out of 48 chemicals belonging to different functional groups) encompassing mostly amines, carboxylic acids or aldehydes and belonging to green leaf volatiles, vertebrate related volatiles and volatiles emitted by standing waters bacteria. The properties of Odonata OSNs are very similar to those of ionotropic receptors (IRs) expressing OSNs in other insects.

  15. The sense of smell in Odonata: an electrophysiological screening.

    Science.gov (United States)

    Piersanti, Silvana; Frati, Francesca; Conti, Eric; Rebora, Manuela; Salerno, Gianandrea

    2014-11-01

    Volatile chemicals mediate a great range of intra- and interspecific signalling and information in insects. Olfaction has been widely investigated mostly in Neoptera while the knowledge of this sense in most basal insects such as Paleoptera (Odonata and Ephemeroptera) is still poor. In the present study we show the results of an electrophysiological screening on two model species, Libellula depressa (Libellulidae) and Ischnura elegans (Coenagrionidae), representatives of the two Odonata suborders Anisoptera and Zygoptera, with the aim to deep the knowledge on the sense of smell of this insect order. The antennal olfactory sensory neurons (OSNs) of these two species responded to the same 22 compounds (out of 48 chemicals belonging to different functional groups) encompassing mostly amines, carboxylic acids or aldehydes and belonging to green leaf volatiles, vertebrate related volatiles and volatiles emitted by standing waters bacteria. The properties of Odonata OSNs are very similar to those of ionotropic receptors (IRs) expressing OSNs in other insects. PMID:25218659

  16. High throughput electrophysiology: new perspectives for ion channel drug discovery

    DEFF Research Database (Denmark)

    Willumsen, Niels J; Bech, Morten; Olesen, Søren-Peter;

    2003-01-01

    Proper function of ion channels is crucial for all living cells. Ion channel dysfunction may lead to a number of diseases, so-called channelopathies, and a number of common diseases, including epilepsy, arrhythmia, and type II diabetes, are primarily treated by drugs that modulate ion channels. A...... introduction of new powerful HTS electrophysiological techniques is predicted to cause a revolution in ion channel drug discovery....... cornerstone in current drug discovery is high throughput screening assays which allow examination of the activity of specific ion channels though only to a limited extent. Conventional patch clamp remains the sole technique with sufficiently high time resolution and sensitivity required for precise and direct...... characterization of ion channel properties. However, patch clamp is a slow, labor-intensive, and thus expensive, technique. New techniques combining the reliability and high information content of patch clamping with the virtues of high throughput philosophy are emerging and predicted to make a number of ion...

  17. Indeterminacy of Spatiotemporal Cardiac Alternans

    CERN Document Server

    Zhao, Xiaopeng

    2007-01-01

    Cardiac alternans, a beat-to-beat alternation in action potential duration (at the cellular level) or in ECG morphology (at the whole heart level), is a marker of ventricular fibrillation, a fatal heart rhythm that kills hundreds of thousands of people in the US each year. Investigating cardiac alternans may lead to a better understanding of the mechanisms of cardiac arrhythmias and eventually better algorithms for the prediction and prevention of such dreadful diseases. In paced cardiac tissue, alternans develops under increasingly shorter pacing period. Existing experimental and theoretical studies adopt the assumption that alternans in homogeneous cardiac tissue is exclusively determined by the pacing period. In contrast, we find that, when calcium-driven alternans develops in cardiac fibers, it may take different spatiotemporal patterns depending on the pacing history. Because there coexist multiple alternans solutions for a given pacing period, the alternans pattern on a fiber becomes unpredictable. Usin...

  18. An overview of cardiac morphogenesis.

    Science.gov (United States)

    Schleich, Jean-Marc; Abdulla, Tariq; Summers, Ron; Houyel, Lucile

    2013-11-01

    Accurate knowledge of normal cardiac development is essential for properly understanding the morphogenesis of congenital cardiac malformations that represent the most common congenital anomaly in newborns. The heart is the first organ to function during embryonic development and is fully formed at 8 weeks of gestation. Recent studies stemming from molecular genetics have allowed specification of the role of cellular precursors in the field of heart development. In this article we review the different steps of heart development, focusing on the processes of alignment and septation. We also show, as often as possible, the links between abnormalities of cardiac development and the main congenital heart defects. The development of animal models has permitted the unraveling of many mechanisms that potentially lead to cardiac malformations. A next step towards a better knowledge of cardiac development could be multiscale cardiac modelling. PMID:24138816

  19. Marshall束电生理特性及相关的房性心律失常%Electrophysiological Characteristics of Marshall Bundle and Its Related Atrial Arrhythmia

    Institute of Scientific and Technical Information of China (English)

    李蕾; 刘书旺(综述)

    2016-01-01

    Although the ligament of Marshall ( LOM) has been implicated in the genesis of atrial arrhythmia , the important cardiac muscle fibers ( Marshall bundles , MB) within this LOM is not well concerned .The paper reviews the anatomy of MB and its electrophysio-logical characteristics and mechanism in atrial arrhythmia .%已知Marshall韧带参与了房性心律失常的发生和维持,然而,其中起关键作用的肌性结构———Marshall束尚无详细报道。现就Marshall束的解剖及其在房性心律失常中的电生理特性、折返机制和研究进展做一综述。

  20. Individual Differences in Reinforcement Learning: Behavioral, Electrophysiological, and Neuroimaging Correlates

    Science.gov (United States)

    Santesso, Diane L.; Dillon, Daniel G.; Birk, Jeffrey L.; Holmes, Avram J.; Goetz, Elena; Bogdan, Ryan; Pizzagalli, Diego A.

    2008-01-01

    During reinforcement learning, phasic modulations of activity in midbrain dopamine neurons are conveyed to the dorsal anterior cingulate cortex (dACC) and basal ganglia and serve to guide adaptive responding. While the animal literature supports a role for the dACC in integrating reward history over time, most human electrophysiological studies of dACC function have focused on responses to single positive and negative outcomes. The present electrophysiological study investigated the role of the dACC in probabilistic reward learning in healthy subjects using a task that required integration of reinforcement history over time. We recorded the feedback-related negativity (FRN) to reward feedback in subjects who developed a response bias toward a more frequently rewarded (“rich”) stimulus (“learners”) versus subjects who did not (“non-learners”). Compared to non-learners, learners showed more positive (i.e., smaller) FRNs and greater dACC activation upon receiving reward for correct identification of the rich stimulus. In addition, dACC activation and a bias to select the rich stimulus were positively correlated. The same participants also completed a monetary incentive delay (MID) task administered during functional magnetic resonance imaging. Compared to non-learners, learners displayed stronger basal ganglia responses to reward in the MID task. These findings raise the possibility that learners in the probabilistic reinforcement task were characterized by stronger dACC and basal ganglia responses to rewarding outcomes. Furthermore, these results highlight the importance of the dACC to probabilistic reward learning in humans. PMID:18595740

  1. Novel electrophysiological approaches to clinical epilepsy. Diagnosis and treatment

    International Nuclear Information System (INIS)

    Seizure onset zone (SOZ) is currently defined by ictal epileptiform discharges, which are most commonly recorded as regional low-voltage fast waves or repetitive spikes. Interictal epileptiform discharges, on the other hand, are not specific enough for SOZ as they are recorded at zones other than the SOZ; they are also recorded from areas that do not generate the ictal pattern and from areas to which ictal discharges propagate. Besides spikes and sharp waves, a novel index of human epileptogenicity has been investigated in association with wide-band electroencephalography (EEG) analysis. We primarily noted the following during clinical neurophysiological analysis for clinical epilepsy. Recent development of digital EEG technology enabled us to record wide-band EEG in a clinical setting. Thus, high frequency (>200 Hz) and low frequency (<1 Hz) components can be reliably recorded using subdural electrodes. Direct current shift, slow shift, ripple, and fast ripple can be well delineated, and they will be potentially useful in the diagnosis and management of epileptic patients. Fiber tractography (morphological parameter) and cortico-cortical-evoked potentials with single cortical stimulation (electrophysiological parameter) elucidated cortico-cortical connections in human brain. The data thus obtained can help us understand the mechanism of seizure propagation and normal cortical functional connectivity. Non-invasive simultaneous recording of EEG and functional magnetic resonance imaging (fMRI) provided information on the roles of deep brain structures associated with scalp-recorded epileptiform discharges. Interventional neurophysiology can shed light on the non-pharmacological treatment of epilepsy. In this report, we discuss these novel electrophysiological approaches to the diagnosis and treatment of clinical epilepsy. (author)

  2. Electrophysiological biomarkers for improved etiological diagnosis of cognitive impairment

    Directory of Open Access Journals (Sweden)

    Yamasaki T

    2014-07-01

    Full Text Available Takao Yamasaki,1,2 Shozo Tobimatsu1 1Department of Clinical Neurophysiology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; 2Department of Neurology, Minkodo Minohara Hospital, Fukuoka, Japan Abstract: Alzheimer's disease (AD, Lewy body disease (LBD, and frontotemporal lobar degeneration (FTLD are three major types of neurodegenerative dementia. Intervention and treatment differ significantly among these major dementias, necessitating early and accurate diagnosis. Patients with AD, LBD, and FTLD exhibit specific patterns of visual dysfunction as early behavioral signs. These visual impairments are the manifestations of topographic patterns of neuropathology specific to each type of dementia. Electrophysiological measurements, such as visual evoked potentials and event-related potentials, are objective and noninvasive tools that can detect subtle functional changes in human brain. Therefore, with the use of visual evoked potentials and event-related potentials, early detection of specific patterns of visual dysfunction may be useful for differential diagnosis of dementia. In this review, we first summarize current knowledge about the relevant aspects of the human visual system. Second, we outline clinical characteristics, including visual perceptual abnormalities, of each type of degenerative dementia. Finally, we describe the application of visual evoked potential and event-related potential recording techniques to study visual perception in patients with mild cognitive impairment (prodromal stage of dementia. We stress that electrophysiological signals have potential as reliable biomarkers in the diagnosis of different types of dementia, especially in the case of overlapping phenotypes. Keywords: Alzheimer's disease, Lewy body disease, frontotemporal lobar degeneration, visual evoked potentials, event-related potentials, parallel visual pathways

  3. Assessment of cardiac conduction: basic principles of optical mapping.

    Science.gov (United States)

    Ding, Chunhua; Everett, Thomas H

    2010-01-01

    Extracellular recordings acquired from electrodes placed on the surface of cardiac tissue have traditionally been used to study the electrophysiological properties of the tissue. While this technique has been used in several studies that have increased our understanding of cardiac arrhythmias and action potential propagation, there are several limitations that have prevented us from seeing a bigger picture of arrhythmia mechanisms. These limitations include the limited number of electrodes and unstable recordings. Optical mapping was developed to increase the temporal and spatial resolution over traditional electrode recordings and ultimately the accuracy of the data analysis. This technology involves using a voltage-sensitive dye that binds to the cell membrane. The fluorescence changes of the dye have a linear relationship to the action potential changes of the cell membrane. These fluorescent changes can then be detected by a photodiode array, a CCD camera or a CMOS camera. This will allow the recording of the action potential in hundreds to thousands of different sites simultaneously. Presented in this chapter are the materials and hardware needed along with step-by-step instructions on setup and techniques used in optical mapping for larger tissue preparations. PMID:20680823

  4. Sudden Cardiac Death in Athletes.

    Science.gov (United States)

    Wasfy, Meagan M; Hutter, Adolph M; Weiner, Rory B

    2016-01-01

    There are clear health benefits to exercise; even so, patients with cardiac conditions who engage in exercise and athletic competition may on rare occasion experience sudden cardiac death (SCD). This article reviews the epidemiology and common causes of SCD in specific athlete populations. There is ongoing debate about the optimal mechanism for SCD prevention, specifically regarding the inclusion of the ECG and/or cardiac imaging in routine preparticipation sports evaluation. This controversy and contemporary screening recommendations are also reviewed. PMID:27486488

  5. Case Report: Penetrating Cardiac Injury

    Directory of Open Access Journals (Sweden)

    Adem Grbolar

    2013-10-01

    Full Text Available Summary: Penetrating cardiac injurys caused by gunshots and penetrating tools have high mortality rates. The way of injury, how the cardiac area is effected and the presence of cardiac tamponadecauses mortality in different rates. However the better treatment quality of hospitals, increasingoperative techniques, and internel care unit quality has not been change during the years. Searching the literature, we want to present a 42 years old male patient whowas injured by knife and had a 1 cm skin wound on chest with cardiac tamponade. After sternotomy a 7 cm laseration was observed in heart. Cardioraphy was performed.

  6. Cardiac Electromechanical Models: From Cell to Organ

    Directory of Open Access Journals (Sweden)

    Natalia A Trayanova

    2011-08-01

    Full Text Available The heart is a multiphysics and multiscale system that has driven the development of the most sophisticated mathematical models at the frontiers of computation physiology and medicine. This review focuses on electromechanical (EM models of the heart from the molecular level of myofilaments to anatomical models of the organ. Because of the coupling in terms of function and emergent behaviors at each level of biological hierarchy, separation of behaviors at a given scale is difficult. Here, a separation is drawn at the cell level so that the first half addresses subcellular/single cell models and the second half addresses organ models. At the subcelluar level, myofilament models represent actin-myosin interaction and Ca-based activation. Myofilament models and their refinements represent an overview of the development in the field. The discussion of specific models emphasizes the roles of cooperative mechanisms and sarcomere length dependence of contraction force, considered the cellular basis of the Frank-Starling law. A model of electrophysiology and Ca handling can be coupled to a myofilament model to produce an EM cell model, and representative examples are summarized to provide an overview of the progression of field. The second half of the review covers organ-level models that require solution of the electrical component as a reaction-diffusion system and the mechanical component, in which active tension generated by the myocytes produces deformation of the organ as described by the equations of continuum mechanics. As outlined in the review, different organ-level models have chosen to use different ionic and myofilament models depending on the specific application; this choice has been largely dictated by compromises between model complexity and computational tractability. The review also addresses application areas of EM models such as cardiac resynchronization therapy and the role of mechano-electric coupling in arrhythmias and

  7. Combination of miRNA499 and miRNA133 exerts a synergic effect on cardiac differentiation.

    Science.gov (United States)

    Pisano, Federica; Altomare, Claudia; Cervio, Elisabetta; Barile, Lucio; Rocchetti, Marcella; Ciuffreda, Maria Chiara; Malpasso, Giuseppe; Copes, Francesco; Mura, Manuela; Danieli, Patrizia; Viarengo, Gianluca; Zaza, Antonio; Gnecchi, Massimiliano

    2015-04-01

    Several studies have demonstrated that miRNA are involved in cardiac development, stem cell maintenance, and differentiation. In particular, it has been shown that miRNA133, miRNA1, and miRNA499 are involved in progenitor cell differentiation into cardiomyocytes. However, it is unknown whether different miRNA may act synergistically to improve cardiac differentiation. We used mouse P19 cells as a cardiogenic differentiation model. miRNA499, miRNA1, or miRNA133 were transiently over-expressed in P19 cells individually or in different combinations. The over-expression of miRNA499 alone increased the number of beating cells and the association of miRNA499 with miRNA133 exerted a synergistic effect, further increasing the number of beating cells. Real-time polymerase chain reaction showed that the combination of miRNA499 + 133 enhanced the expression of cardiac genes compared with controls. Western blot and immunocytochemistry for connexin43 and cardiac troponin T confirmed these findings. Importantly, caffeine responsiveness, a clear functional parameter of cardiac differentiation, was increased by miRNA499 in association with miRNA133 and was directly correlated with the activation of the cardiac troponin I isoform promoter. Cyclic contractions were reversibly abolished by extracellular calcium depletion, nifedipine, ryanodine, and IP3R blockade. Finally, we demonstrated that the use of miRNA499 + 133 induced cardiac differentiation even in the absence of dimethyl sulfoxide. Our results show that the areas spontaneously contracting possess electrophysiological and pharmacological characteristics compatible with true cardiac excitation-contraction coupling. The translational relevance of our findings was reinforced by the demonstration that the over-expression of miRNA499 and miRNA133 was also able to induce the differentiation of human mesenchymal stromal cells toward the cardiac lineage. PMID:25534971

  8. Preventing tomorrow's sudden cardiac death today: part I: Current data on risk stratification for sudden cardiac death.

    Science.gov (United States)

    Al-Khatib, Sana M; Sanders, Gillian D; Bigger, J Thomas; Buxton, Alfred E; Califf, Robert M; Carlson, Mark; Curtis, Anne; Curtis, Jeptha; Fain, Eric; Gersh, Bernard J; Gold, Michael R; Haghighi-Mood, Ali; Hammill, Stephen C; Healey, Jeff; Hlatky, Mark; Hohnloser, Stefan; Kim, Raymond J; Lee, Kerry; Mark, Daniel; Mianulli, Marcus; Mitchell, Brent; Prystowsky, Eric N; Smith, Joseph; Steinhaus, David; Zareba, Wojciech

    2007-06-01

    Accurate and timely prediction of sudden cardiac death (SCD) is a necessary prerequisite for effective prevention and therapy. Although the largest number of SCD events occurs in patients without overt heart disease, there are currently no tests that are of proven predictive value in this population. Efforts in risk stratification for SCD have focused primarily on predicting SCD in patients with known structural heart disease. Despite the ubiquity of tests that have been purported to predict SCD vulnerability in such patients, there is little consensus on which test, in addition to the left ventricular ejection fraction, should be used to determine which patients will benefit from an implantable cardioverter defibrillator. On July 20 and 21, 2006, a group of experts representing clinical cardiology, cardiac electrophysiology, biostatistics, economics, and health policy were joined by representatives of the US Food and Drug administration, Centers for Medicare Services, Agency for Health Research and Quality, the Heart Rhythm Society, and the device and pharmaceutical industry for a round table meeting to review current data on strategies of risk stratification for SCD, to explore methods to translate these strategies into practice and policy, and to identify areas that need to be addressed by future research studies. The meeting was organized by the Duke Center for the Prevention of SCD at the Duke Clinical Research Institute and was funded by industry participants. This article summarizes the presentations and discussions that occurred at that meeting.

  9. Antifibrinolytics in cardiac surgery

    Directory of Open Access Journals (Sweden)

    Achal Dhir

    2013-01-01

    Full Text Available Cardiac surgery exerts a significant strain on the blood bank services and is a model example in which a multi-modal blood-conservation strategy is recommended. Significant bleeding during cardiac surgery, enough to cause re-exploration and/or blood transfusion, increases morbidity and mortality. Hyper-fibrinolysis is one of the important contributors to increased bleeding. This knowledge has led to the use of anti-fibrinolytic agents especially in procedures performed under cardiopulmonary bypass. Nothing has been more controversial in recent times than the aprotinin controversy. Since the withdrawal of aprotinin from the world market, the choice of antifibrinolytic agents has been limited to lysine analogues either tranexamic acid (TA or epsilon amino caproic acid (EACA. While proponents of aprotinin still argue against its non-availability. Health Canada has approved its use, albeit under very strict regulations. Antifibrinolytic agents are not without side effects and act like double-edged swords, the stronger the anti-fibrinolytic activity, the more serious the side effects. Aprotinin is the strongest in reducing blood loss, blood transfusion, and possibly, return to the operating room after cardiac surgery. EACA is the least effective, while TA is somewhere in between. Additionally, aprotinin has been implicated in increased mortality and maximum side effects. TA has been shown to increase seizure activity, whereas, EACA seems to have the least side effects. Apparently, these agents do not differentiate between pathological and physiological fibrinolysis and prevent all forms of fibrinolysis leading to possible thrombotic side effects. It would seem prudent to select the right agent knowing its risk-benefit profile for a given patient, under the given circumstances.

  10. A molecular switch driving inactivation in the cardiac K+ channel HERG.

    Directory of Open Access Journals (Sweden)

    David A Köpfer

    Full Text Available K(+ channels control transmembrane action potentials by gating open or closed in response to external stimuli. Inactivation gating, involving a conformational change at the K(+ selectivity filter, has recently been recognized as a major K(+ channel regulatory mechanism. In the K(+ channel hERG, inactivation controls the length of the human cardiac action potential. Mutations impairing hERG inactivation cause life-threatening cardiac arrhythmia, which also occur as undesired side effects of drugs. In this paper, we report atomistic molecular dynamics simulations, complemented by mutational and electrophysiological studies, which suggest that the selectivity filter adopts a collapsed conformation in the inactivated state of hERG. The selectivity filter is gated by an intricate hydrogen bond network around residues S620 and N629. Mutations of this hydrogen bond network are shown to cause inactivation deficiency in electrophysiological measurements. In addition, drug-related conformational changes around the central cavity and pore helix provide a functional mechanism for newly discovered hERG activators.

  11. Cardiac arrest – cardiopulmonary resuscitation

    Directory of Open Access Journals (Sweden)

    Basri Lenjani

    2014-01-01

    Conclusions: All survivors from cardiac arrest have received appropriate medical assistance within 10 min from attack, which implies that if cardiac arrest occurs near an institution health care (with an opportunity to provide the emergent health care the rate of survival is higher.

  12. Leadership in cardiac surgery.

    Science.gov (United States)

    Rao, Christopher; Patel, Vanash; Ibrahim, Michael; Ahmed, Kamran; Wong, Kathie A; Darzi, Ara; von Segesser, Ludwig K; Athanasiou, Thanos

    2011-06-01

    Despite the efficacy of cardiac surgery, less invasive interventions with more uncertain long-term outcomes are increasingly challenging surgery as first-line treatment for several congenital, degenerative and ischemic cardiac diseases. The specialty must evolve if it is to ensure its future relevance. More importantly, it must evolve to ensure that future patients have access to treatments with proven long-term effectiveness. This cannot be achieved without dynamic leadership; however, our contention is that this is not enough. The demands of a modern surgical career and the importance of the task at hand are such that the serendipitous emergence of traditional charismatic leadership cannot be relied upon to deliver necessary change. We advocate systematic analysis and strategic leadership at a local, national and international level in four key areas: Clinical Care, Research, Education and Training, and Stakeholder Engagement. While we anticipate that exceptional individuals will continue to shape the future of our specialty, the creation of robust structures to deliver collective leadership in these key areas is of paramount importance. PMID:20884217

  13. Interventional cardiac catheterization.

    Science.gov (United States)

    Pihkala, J; Nykanen, D; Freedom, R M; Benson, L N

    1999-04-01

    Over the past decade, transcatheter interventions have become increasingly important in the treatment of patients with congenital heart lesions. These procedures may be broadly grouped as dilations (e.g., septostomy, valvuloplasty, angioplasty, and endovascular stenting) or as closures (e.g., vascular embolization and device closure of defects). Balloon valvuloplasty has become the treatment of choice for patients in all age groups with simple valvar pulmonic stenosis and, although not curative, seems at least comparable to surgery for congenital aortic stenosis in newborns to young adults. Balloon angioplasty is successfully applied to a wide range of aortic, pulmonary artery, and venous stenoses. Stents are useful in dilating lesions of which the intrinsic elasticity results in vessel recoil after balloon dilation alone. Catheter-delivered coils are used to embolize a wide range of arterial, venous, and prosthetic vascular connections. Although some devices remain investigational, they have been successfully used for closure of many arterial ducts and atrial and ventricular septal defects. In the therapy for patients with complex CHD, best results may be achieved by combining cardiac surgery with interventional catheterization. The cooperation among interventional cardiologists and cardiac surgeons was highlighted in a report of an algorithm to manage patients with tetralogy of Fallot or pulmonary atresia with diminutive pulmonary arteries, involving balloon dilation, coil embolization of collaterals, and intraoperative stent placement. In this setting, well-planned catheterization procedures have an important role in reducing the overall number of procedures that patients may require over a lifetime, with improved outcomes.

  14. Ictal Cardiac Ryhthym Abnormalities.

    Science.gov (United States)

    Ali, Rushna

    2016-01-01

    Cardiac rhythm abnormalities in the context of epilepsy are a well-known phenomenon. However, they are under-recognized and often missed. The pathophysiology of these events is unclear. Bradycardia and asystole are preceded by seizure onset suggesting ictal propagation into the cortex impacting cardiac autonomic function, and the insula and amygdala being possible culprits. Sudden unexpected death in epilepsy (SUDEP) refers to the unanticipated death of a patient with epilepsy not related to status epilepticus, trauma, drowning, or suicide. Frequent refractory generalized tonic-clonic seizures, anti-epileptic polytherapy, and prolonged duration of epilepsy are some of the commonly identified risk factors for SUDEP. However, the most consistent risk factor out of these is an increased frequency of generalized tonic-clonic seizures (GTC). Prevention of SUDEP is extremely important in patients with chronic, generalized epilepsy. Since increased frequency of GTCS is the most consistently reported risk factor for SUDEP, effective seizure control is the most important preventive strategy. PMID:27347227

  15. Pneumothorax in cardiac pacing

    DEFF Research Database (Denmark)

    Kirkfeldt, Rikke Esberg; Johansen, Jens Brock; Nohr, Ellen Aagaard;

    2012-01-01

    AIM: To identify risk factors for pneumothorax treated with a chest tube after cardiac pacing device implantation in a population-based cohort.METHODS AND RESULTS: A nationwide cohort study was performed based on data on 28 860 patients from the Danish Pacemaker Register, which included all Danish...... patients who received their first pacemaker (PM) or cardiac resynchronization device from 1997 to 2008. Multiple logistic regression was used to estimate adjusted odds ratios (aOR) with 95% confidence intervals for the association between risk factors and pneumothorax treated with a chest tube. The median...... age was 77 years (25th and 75th percentile: 69-84) and 55% were male (n = 15 785). A total of 190 patients (0.66%) were treated for pneumothorax, which was more often in women [aOR 1.9 (1.4-2.6)], and in patients with age >80 years [aOR 1.4 (1.0-1.9)], a prior history of chronic obstructive pulmonary...

  16. Electrophysiological evaluation in 4 patients with diabetic pseudotabes

    Institute of Scientific and Technical Information of China (English)

    Xiaofang Cai; Qionghua Huang

    2007-01-01

    BACKGROUND: Researches on diabetic nervous system lesion are mainly focus on peripheral nerve and vegetative nerve, so there are few investigations on diabetic pseudotabes. OBJECTIVE: To investigate the electrophysiological examinations on the diagnosis of diabetic pseudotabes. DESIGN: Case study. SETTING: Department of Electrophysiology and Department of Neurology, Zhongshan Hospital Affiliated to Xiamen University. PARTICIPANTS: A total of 4 patients with type 2 diabetes mellitus, including 3 males and 1 female aged from 50 to 72 years, were selected from Department of Neurology, Zhongshan Hospital Affiliated to Xiamen University from March 2002 to February 2005. All accepted subjects met the modified diagnostic criteria of diabetes mellitus, which was set by American Diabetes Mellitus Association (ADA) in 1997. Otherwise, the subjects had typical symptoms and physical signs of spinal posterior funiculus damage. However, patients with spinal cord lesion which was caused by other factors were excluded. All accepted subjects provided the confirmed consent.METHODS: Nicolet NT electromyography (EMG)/evoked potential meter (made in the USA) was used to detect spinal cord conduction velocity (SCCV), somatosensory evoked potential (SEP) of lower limbs, motor nerve conduction velocity (MNCV) and sensory nerve conduction velocity (SNCV) of extremities.Determining criteria: Measurements were performed based on the laboratory standards. SCCV, which was less than lower limit of normal value (T2-12: 40 - 55 m/s, Ti2 - L4: 20-41 m/s, T2 - L4: 36 - 45 m/s), was regarded as abnormal. SEP value of lower limbs: P40, P60 and PF, which were more than standard deviation of normal value (-x+2.5), were regarded as the abnormality. Normal value of P40, P60 and PF latencies (-x + s) in this study: P40, P60 and PF in males were (37.6±1.9) ms, (59.8±3.9) ms and (7.6±0.9) ms, respectively; meanwhile, those in females were (35.5±1.7) ms, (55.2±2.7) ms and (6.3±0.7) ms, respectively

  17. Radiofrequency and microwave tumor ablation in patients with implanted cardiac devices: Is it safe?

    Energy Technology Data Exchange (ETDEWEB)

    Skonieczki, Brendan D., E-mail: bskonieczki@lifespan.org [Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University/Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 (United States); Wells, Catherine, E-mail: cwells1@bidmc.harvard.edu [Department of Radiology, Harvard Medical School/Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215 (United States); Wasser, Elliot J., E-mail: ewasser@lifespan.org [Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University/Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 (United States); Dupuy, Damian E., E-mail: ddupuy@lifespan.org [Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University/Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903 (United States)

    2011-09-15

    Purpose: To identify malfunction of implanted cardiac devices during or after thermal ablation of tumors in lung, kidney, liver or bone, using radiofrequency (RF) or microwave (MW) energy. Materials and methods: After providing written consent, 19 patients (15 men and 4 women; mean age 78 years) with pacemakers or pacemaker/defibrillators underwent 22 CT image-guided percutaneous RF or MW ablation of a variety of tumors. Before and after each procedure, cardiac devices were interrogated and reprogrammed by a trained cardiac electrophysiology fellow. Possible pacer malfunctions included abnormalities on electrocardiographic (EKG) monitoring and alterations in device settings. Our institutional review board approved this Health Insurance Portability and Accountability Act-compliant study. Informed consent for participation in this retrospective study was deemed unnecessary by our review board. Results: During 20 of 22 sessions, no abnormalities were identified in continuous, EKG tracings or pacemaker functions. However, in two sessions significant changes, occurred in pacemaker parameters: inhibition of pacing during RF application in one, session and resetting of mode by RF energy in another session. These changes did not, result in hemodynamic instability of either patient. MW ablation was not associated with, any malfunction. In all 22 sessions, pacemakers were undamaged and successfully reset to original parameters. Conclusion: RF or MW ablation of tumors in liver, kidney, bone and lung can be performed safely in patients with permanent intra-cardiac devices, but careful planning between radiology and cardiology is essential to avoid adverse outcomes.

  18. Signs of cardiac autonomic imbalance and proarrhythmic remodeling in FTO deficient mice.

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    Luca Carnevali

    Full Text Available In humans, variants of the fat mass and obesity associated (FTO gene have recently been associated with obesity. However, the physiological function of FTO is not well defined. Previous investigations in mice have linked FTO deficiency to growth retardation, loss of white adipose tissue, increased energy metabolism and enhanced systemic sympathetic activation. In this study we investigated for the first time the effects of global knockout of the mouse FTO gene on cardiac function and its autonomic neural regulation. ECG recordings were acquired via radiotelemetry in homozygous knockout (n = 12 and wild-type (n = 8 mice during resting and stress conditions, and analyzed by means of time- and frequency-domain indexes of heart rate variability. In the same animals, cardiac electrophysiological properties (assessed by epicardial mapping and structural characteristics were investigated. Our data indicate that FTO knockout mice were characterized by (i higher heart rate values during resting and stress conditions, (ii heart rate variability changes (increased LF to HF ratio, (iii larger vulnerability to stress-induced tachyarrhythmias, (iv altered ventricular repolarization, and (v cardiac hypertrophy compared to wild-type counterparts. We conclude that FTO deficiency in mice leads to an imbalance of the autonomic neural modulation of cardiac function in the sympathetic direction and to a potentially proarrhythmic remodeling of electrical and structural properties of the heart.

  19. Affect intensity and cardiac arousal.

    Science.gov (United States)

    Blascovich, J; Brennan, K; Tomaka, J; Kelsey, R M; Hughes, P; Coad, M L; Adlin, R

    1992-07-01

    Relationships between affect intensity and basal, evoked, and perceived cardiac arousal were investigated in 3 experiments. Affect intensity was assessed using Larsen and Diener's (1987) Affect Intensity Measure (AIM). Cardiac arousal was evoked with exercise in the 1st study and with mental arithmetic in the 2nd and 3rd. Perceived cardiac arousal was measured under optimal conditions using a standard heartbeat discrimination procedure. Women as a group scored higher on the AIM. Affect intensity was unrelated to basal or evoked cardiac arousal and was negatively related to perceived cardiac arousal in all 3 studies. Data suggest that affect intensity, although unrelated to actual physiological arousal, is negatively related to the accuracy with which individuals perceive their own arousal. Results are discussed within the context of an expanded arousal-regulation model (Blascovich, 1990). PMID:1494983

  20. Direct cooling of the catheter tip increases safety for CMR-guided electrophysiological procedures

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    Reiter Theresa

    2012-02-01

    Full Text Available Abstract Background One of the safety concerns when performing electrophysiological (EP procedures under magnetic resonance (MR guidance is the risk of passive tissue heating due to the EP catheter being exposed to the radiofrequency (RF field of the RF transmitting body coil. Ablation procedures that use catheters with irrigated tips are well established therapeutic options for the treatment of cardiac arrhythmias and when used in a modified mode might offer an additional system for suppressing passive catheter heating. Methods A two-step approach was chosen. Firstly, tests on passive catheter heating were performed in a 1.5 T Avanto system (Siemens Healthcare Sector, Erlangen, Germany using a ASTM Phantom in order to determine a possible maximum temperature rise. Secondly, a phantom was designed for simulation of the interface between blood and the vascular wall. The MR-RF induced temperature rise was simulated by catheter tip heating via a standard ablation generator. Power levels from 1 to 6 W were selected. Ablation duration was 120 s with no tip irrigation during the first 60 s and irrigation at rates from 2 ml/min to 35 ml/min for the remaining 60 s (Biotronik Qiona Pump, Berlin, Germany. The temperature was measured with fluoroscopic sensors (Luxtron, Santa Barbara, CA, USA at a distance of 0 mm, 2 mm, 4 mm, and 6 mm from the catheter tip. Results A maximum temperature rise of 22.4°C at the catheter tip was documented in the MR scanner. This temperature rise is equivalent to the heating effect of an ablator's power output of 6 W at a contact force of the weight of 90 g (0.883 N. The catheter tip irrigation was able to limit the temperature rise to less than 2°C for the majority of examined power levels, and for all examined power levels the residual temperature rise was less than 8°C. Conclusion Up to a maximum of 22.4°C, the temperature rise at the tissue surface can be entirely suppressed by using the catheter's own irrigation

  1. Induced pluripotent stem cell derived cardiomyocytes as models for cardiac arrhythmias

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    Maaike eHoekstra

    2012-08-01

    Full Text Available Cardiac arrhythmias are a major cause of morbidity and mortality. In younger patients, the majority of sudden cardiac deaths have an underlying Mendelian genetic cause. Over the last 15 years, enormous progress has been made in identifying the distinct clinical phenotypes and in studying the basic cellular and genetic mechanisms associated with the primary Mendelian (monogenic arrhythmia syndromes. Investigation of the electrophysiological consequences of an ion channel mutation is ideally done in the native cardiomyocyte environment. However, the majority of such studies so far have relied on heterologous expression systems in which single ion channel genes are expressed in non-cardiac cells. In some cases, transgenic mouse models haven been generated, but these also have significant shortcomings, primarily related to species differences.The discovery that somatic cells can be reprogrammed to pluripotency as induced pluripotent stem cells (iPSC has generated much interest since it presents an opportunity to generate patient- and disease-specific cell lines from which normal and diseased human cardiomyocytes can be obtained These genetically diverse human model systems can be studied in vitro and used to decipher mechanisms of disease and identify strategies and reagents for new therapies. Here we review the present state of the art with respect to cardiac disease models already generated using IPSC technology and which have been (partially characterized.Human iPSC (hiPSC models have been described for the cardiac arrhythmia syndromes, including LQT1, LQT2, LQT3-Brugada Syndrome, LQT8/Timothy syndrome and catecholaminergic polymorphic ventricular tachycardia. In most cases, the hiPSC-derived cardiomyoctes recapitulate the disease phenotype and have already provided opportunities for novel insight into cardiac pathophysiology. It is expected that the lines will be useful in the development of pharmacological agents for the management of these

  2. Subthalamic Nucleus High-Frequency Stimulation Restores Altered Electrophysiological Properties of Cortical Neurons in Parkinsonian Rat

    OpenAIRE

    Bertrand Degos; Jean-Michel Deniau; Mario Chavez; Nicolas Maurice

    2013-01-01

    Electrophysiological recordings performed in parkinsonian patients and animal models have confirmed the occurrence of alterations in firing rate and pattern of basal ganglia neurons, but the outcome of these changes in thalamo-cortical networks remains unclear. Using rats rendered parkinsonian, we investigated, at a cellular level in vivo, the electrophysiological changes induced in the pyramidal cells of the motor cortex by the dopaminergic transmission interruption and further characterized...

  3. The assessment of visually impaired persons working capacities using electrophysiological and ophthalmic ergonomics methods

    OpenAIRE

    M. I. Razumovsky; O. E. Kolyuka; A. M. Razumovskaya

    2014-01-01

    Aim was to analyze working capacities of visually impaired persons by means of complex electrophysiological and ophthalmic ergonomics eye examination.Materials and methods. Standard clinical ophthalmologic examination (visual acuity measurement, refractometry, biomicroscopy, ophthalmoscopy) as well as electrophysiological (electrooculography, electrical sensitivity of the eye, critical flicker fusion frequency) and ophthalmic ergonomics tests (accommodation measurement, professional testing u...

  4. Electrophysiological Correlates of Long-Term Soto Zen Meditation

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    Henrique Adam Pasquini

    2015-01-01

    Full Text Available This study aimed to verify the electrophysiological correlates of the changes in long-term regular meditators. We use modern techniques of high-resolution electroencephalography applied to slow potentials, power spectra, and potencies related to the events. To obtain encephalographic records, we use an assembly of 128 channels in 31 subjects (17 Soto Zen Buddhist meditators. The motivation of this study was to determine whether the induced beta power would present an increase in meditators as well as a decrease in induced theta/beta ratio in absolute and relative values. However, opposite to what we expected, no significant change was found in the beta frequency. In contrast, the main findings of the study were correlations between the frequency of weekly meditation practice and the increased theta induced relative power, increase of induced power ratio (ratio theta/beta, and increase of the ratio of induced relative powers (theta/beta ratio during our task that featured an “adapted meditation,” suggesting that the meditative state of “mindfulness” is much more related to the permittivity of “distractions” by the meditators, with a deliberate reduction of attention.

  5. Processing fluency hinders subsequent recollection: An electrophysiological study

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    Bingbing eLi

    2015-06-01

    Full Text Available Although many behavioural studies have investigated the effect of processing fluency on subsequent recognition memory, little research has examined the neural mechanism of this phenomenon. The present study aimed to explore the electrophysiological correlates of the effects of processing fluency on subsequent recognition memory by using an event-related potential (ERP approach. The masked repetition priming paradigm was used to manipulate processing fluency in the study phase, and the R/K paradigm was utilised to investigate which recognition memory process (familiarity or recollection was affected by processing fluency in the test phase. Converging behavioural and ERP results indicated that increased processing fluency impaired subsequent recollection. Results from the analysis of ERP priming effects in the study phase indicated that increased perceptual processing fluency of object features, reflected by the N/P 190 priming effect, can hinder encoding activities, reflected by the LPC priming effect, which leads to worse subsequent recollection based recognition memory. These results support the idea that processing fluency can influence subsequent recognition memory and provide a potential neural mechanism underlying this effect. However, further studies are needed to examine whether processing fluency can affect subsequent familiarity.

  6. The electrophysiological underpinnings of processing gender stereotypes in language.

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    Anna Siyanova-Chanturia

    Full Text Available Despite the widely documented influence of gender stereotypes on social behaviour, little is known about the electrophysiological substrates engaged in the processing of such information when conveyed by language. Using event-related brain potentials (ERPs, we examined the brain response to third-person pronouns (lei "she" and lui "he" that were implicitly primed by definitional (passeggera(FEM "passenger", pensionato(MASC "pensioner", or stereotypical antecedents (insegnante "teacher", conducente "driver". An N400-like effect on the pronoun emerged when it was preceded by a definitionally incongruent prime (passeggera(FEM--lui; pensionato(MASC--lei, and a stereotypically incongruent prime for masculine pronouns only (insegnante--lui. In addition, a P300-like effect was found when the pronoun was preceded by definitionally incongruent primes. However, this effect was observed for female, but not male participants. Overall, these results provide further evidence for on-line effects of stereotypical gender in language comprehension. Importantly, our results also suggest a gender stereotype asymmetry in that male and female stereotypes affected the processing of pronouns differently.

  7. Electrophysiological CNS-processes related to associative learning in humans.

    Science.gov (United States)

    Christoffersen, Gert R J; Schachtman, Todd R

    2016-01-01

    The neurophysiology of human associative memory has been studied with electroencephalographic techniques since the 1930s. This research has revealed that different types of electrophysiological processes in the human brain can be modified by conditioning: sensory evoked potentials, sensory induced gamma-band activity, periods of frequency-specific waves (alpha and beta waves, the sensorimotor rhythm and the mu-rhythm) and slow cortical potentials. Conditioning of these processes has been studied in experiments that either use operant conditioning or repeated contingent pairings of conditioned and unconditioned stimuli (classical conditioning). In operant conditioning, the appearance of a specific brain process is paired with an external stimulus (neurofeedback) and the feedback enables subjects to obtain varying degrees of control of the CNS-process. Such acquired self-regulation of brain activity has found practical uses for instance in the amelioration of epileptic seizures, Autism Spectrum Disorders (ASD) and Attention Deficit Hyperactivity Disorder (ADHD). It has also provided communicative means of assistance for tetraplegic patients through the use of brain computer interfaces. Both extra and intracortically recorded signals have been coupled with contingent external feedback. It is the aim for this review to summarize essential results on all types of electromagnetic brain processes that have been modified by classical or operant conditioning. The results are organized according to type of conditioned EEG-process, type of conditioning, and sensory modalities of the conditioning stimuli.

  8. Combined expectancies: electrophysiological evidence for the adjustment of expectancy effects

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    Münte Thomas F

    2006-05-01

    Full Text Available Abstract Background When subjects use cues to prepare for a likely stimulus or a likely response, reaction times are facilitated by valid cues but prolonged by invalid cues. In studies on combined expectancy effects, two cues can independently give information regarding two dimensions of the forthcoming task. In certain situations, cueing effects on one dimension are reduced when the cue on the other dimension is invalid. According to the Adjusted Expectancy Model, cues affect different processing levels and a mechanism is presumed which is sensitive to the validity of early level cues and leads to online adjustment of expectancy effects at later levels. To examine the predictions of this model cueing of stimulus modality was combined with response cueing. Results Behavioral measures showed the interaction of cueing effects. Electrophysiological measures of the lateralized readiness potential (LRP and the N200 amplitude confirmed the predictions of the model. The LRP showed larger effects of response cues on response activation when modality cues were valid rather than invalid. N200 amplitude was largest with valid modality cues and invalid response cues, medium with invalid modality cues, and smallest with two valid cues. Conclusion Findings support the view that the validity of early level expectancies modulates the effects of late level expectancies, which included response activation and response conflict in the present study.

  9. High throughput electrophysiology: new perspectives for ion channel drug discovery.

    Science.gov (United States)

    Willumsen, Niels J; Bech, Morten; Olesen, Søren-Peter; Jensen, Bo Skaaning; Korsgaard, Mads P G; Christophersen, Palle

    2003-01-01

    Proper function of ion channels is crucial for all living cells. Ion channel dysfunction may lead to a number of diseases, so-called channelopathies, and a number of common diseases, including epilepsy, arrhythmia, and type II diabetes, are primarily treated by drugs that modulate ion channels. A cornerstone in current drug discovery is high throughput screening assays which allow examination of the activity of specific ion channels though only to a limited extent. Conventional patch clamp remains the sole technique with sufficiently high time resolution and sensitivity required for precise and direct characterization of ion channel properties. However, patch clamp is a slow, labor-intensive, and thus expensive, technique. New techniques combining the reliability and high information content of patch clamping with the virtues of high throughput philosophy are emerging and predicted to make a number of ion channel targets accessible for drug screening. Specifically, genuine HTS parallel processing techniques based on arrays of planar silicon chips are being developed, but also lower throughput sequential techniques may be of value in compound screening, lead optimization, and safety screening. The introduction of new powerful HTS electrophysiological techniques is predicted to cause a revolution in ion channel drug discovery.

  10. First steps towards initial registration for electrophysiology procedures

    Science.gov (United States)

    Brost, Alexander; Bourier, Felix; Yatziv, Liron; Koch, Martin; Hornegger, Joachim; Strobel, Norbert; Kurzidim, Klaus

    2011-03-01

    Atrial fibrillation is the most common heart arrhythmia and a leading cause of stroke. The treatment option of choice is radio-frequency catheter ablation, which is performed in electrophysiology labs using C-Arm X-ray systems for navigation and guidance. The goal is to electrically isolate the pulmonary vein-left atrial junction thereby rendering myocardial fibers responsible for induction and maintenance of AF inactive. The use of overlay images for fluoroscopic guidance may improve the quality of the ablation procedure, and can reduce procedure time. Overlay images, acquired using CT, MRI, or C-arm CT, can add soft-tissue information, otherwise not visible under X-ray. MRI can be used to image a wide variety of anatomical details without ionizing radiation. In this paper, we present a method to register a 3-D MRI volume to 2-D biplane X-ray images using the coronary sinus. Current approaches require registration of the overlay images to the fluoroscopic images to be performed after the trans-septal puncture, when contast agent can be administered. We present a new approach for registration to align overlay images before the trans-septal puncture. To this end, we manually extract the coronary sinus from pre-operative MRI and register it to a multi-electorde catheter placed in the coronary sinus.

  11. Perception of Chinese poem and its electrophysiological effects.

    Science.gov (United States)

    Li, W; Yang, Y

    2010-07-14

    A neural correlate for phrase boundary perception in language has recently been identified as a reliable and replicable brain effect. It is called the closure positive shift (CPS) and has an equivalent in the perception of music (music CPS). Nevertheless, either in language or in music, this component is elicited by phrase boundary embedded in sentence or melody. Poetry, as the interlude of language and music, is a special kind of discourse and promising material to explore prosodic boundary processing beyond sentence level. The aim of the present study was to investigate the cognitive processing of hierarchical prosodic boundaries in Chinese Tang poem using rhythm matching task. There are generally four hierarchical levels in each poem, including foot boundary, phonological phrase boundary, intonational phrase boundary, and couplet boundary. The electrophysiological results indicated that all the prosodic boundaries of different levels in poems could give rise to the CPS reflecting prosodic phrasing. Furthermore, as the prosodic hierarchical level became higher, the onset latency of the CPS got longer, suggesting the influence of retrospective processing of former information. With regard to the amplitude, we analyzed the CPS amplitude in every 100 ms time window. It was showed that phonological phrase boundary elicited higher CPS amplitude as compared to that evoked by couplet boundary in an earlier time window, whereas in a later time window both of them were lower than the CPS correlated to intonational phrase boundary. The present results further shape our understanding of the CPS component and its relation to the processes involved in prosodic phrasing.

  12. Correlation between muscle electrophysiology and strength after fibular nerve injury.

    Science.gov (United States)

    Won, Yu Hui; Kim, Kang-Won; Choi, Jun Tak; Ko, Myoung-Hwan; Park, Sung-Hee; Seo, Jeong-Hwan

    2016-08-01

    Muscle strength measurement is important when evaluating the degree of impairment in patients with nerve injury. However, accurate and objective evaluation may be difficult in patients with severe pain or those who intentionally try to avoid full exertion. We investigated the usefulness of the affected-to-unaffected side electrophysiological parameter ratios as a measure of objective ankle dorsiflexion (ADF) strength in patients with unilateral fibular nerve injury (FNI). ADF strength was measured in patients with FNI via handheld dynamometer and manual muscle test (MMT). Fibular nerve compound muscle action potential (CMAP) amplitude and latency and ADF strength of the affected side were presented as ratios to the corresponding measurements of the unaffected side. We analysed the correlation of the CMAP ratio with the ADF strength ratio using a dynamometer and compared the CMAP ratios according to MMT grade. Fifty-two patients with FNI were enrolled. The mean CMAP latency ratio did not differ between MMT groups (p = 0.573). The CMAP amplitude ratio proportionally increased with the quantified ADF strength ratio via dynamometer increase (ρ = 0.790; p CMAP latency ratio and the quantified ADF strength ratio did not significantly correlate (ρ = 0.052; p = 0.713). The average CMAP amplitude ratio significantly differed between MMT groups (p CMAP amplitude ratio, might be sensitive parameters for ADF power estimation after FNI. PMID:27142447

  13. Fractal mechanisms in the electrophysiology of the heart

    Science.gov (United States)

    Goldberger, A. L.

    1992-01-01

    The mathematical concept of fractals provides insights into complex anatomic branching structures that lack a characteristic (single) length scale, and certain complex physiologic processes, such as heart rate regulation, that lack a single time scale. Heart rate control is perturbed by alterations in neuro-autonomic function in a number of important clinical syndromes, including sudden cardiac death, congestive failure, cocaine intoxication, fetal distress, space sickness and physiologic aging. These conditions are associated with a loss of the normal fractal complexity of interbeat interval dynamics. Such changes, which may not be detectable using conventional statistics, can be quantified using new methods derived from "chaos theory.".

  14. Physics of Cardiac Arrhythmogenesis

    Science.gov (United States)

    Karma, Alain

    2013-04-01

    A normal heartbeat is orchestrated by the stable propagation of an excitation wave that produces an orderly contraction. In contrast, wave turbulence in the ventricles, clinically known as ventricular fibrillation (VF), stops the heart from pumping and is lethal without prompt defibrillation. I review experimental, computational, and theoretical studies that have shed light on complex dynamical phenomena linked to the initiation, maintenance, and control of wave turbulence. I first discuss advances made to understand the precursor state to a reentrant arrhythmia where the refractory period of cardiac tissue becomes spatiotemporally disordered; this is known as an arrhythmogenic tissue substrate. I describe observed patterns of transmembrane voltage and intracellular calcium signaling that can contribute to this substrate, and symmetry breaking instabilities to explain their formation. I then survey mechanisms of wave turbulence and discuss novel methods that exploit electrical pacing stimuli to control precursor patterns and low-energy pulsed electric fields to control turbulence.

  15. Mediastinitis after cardiac transplantation

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    Noedir A. G. Stolf

    2000-05-01

    Full Text Available OBJECTIVE: Assessment of incidence and behavior of mediastinitis after cardiac transplantation. METHODS: From 1985 to 1999, 214 cardiac transplantations were performed, 12 (5.6% of the transplanted patients developed confirmed mediastinitis. Patient's ages ranged from 42 to 66 years (mean of 52.3±10.0 years and 10 (83.3% patients were males. Seven (58.3% patients showed sternal stability on palpation, 4 (33.3% patients had pleural empyema, and 2 (16.7% patients did not show purulent secretion draining through the wound. RESULTS: Staphylococcus aureus was the infectious agent identified in the wound secretion or in the mediastinum, or both, in 8 (66.7% patients. Staphylococcus epidermidis was identified in 2 (16.7% patients, Enterococcus faecalis in 1 (8.3% patient, and the cause of mediastinitis could not be determined in 1 (8.3% patient. Surgical treatment was performed on an emergency basis, and the extension of the débridement varied with local conditions. In 2 (16.7% patients, we chose to leave the surgical wound open and performed daily dressings with granulated sugar. Total sternal resection was performed in only 1 (8.3% patient. Out of this series, 5 (41.7% patients died, and the causes of death were related to the infection. Autopsy revealed persistence of mediastinitis in 1 (8.3% patient. CONCLUSION: Promptness in diagnosing mediastinitis and precocious surgical drainage have changed the natural evolution of this disease. Nevertheless, observance of the basic precepts of prophylaxis of infection is still the best way to treat mediastinitis.

  16. Platelets and cardiac arrhythmia

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    Jonas S De Jong

    2010-12-01

    Full Text Available Sudden cardiac death remains one of the most prevalent modes of death in industrialized countries, and myocardial ischemia due to thrombotic coronary occlusion is its primary cause. The role of platelets in the occurrence of SCD extends beyond coronary flow impairment by clot formation. Here we review the substances released by platelets during clot formation and their arrhythmic properties. Platelet products are released from three types of platelet granules: dense core granules, alpha-granules, and platelet lysosomes. The physiologic properties of dense granule products are of special interest as a potential source of arrhythmic substances. They are released readily upon activation and contain high concentrations of serotonin, histamine, purines, pyrimidines, and ions such as calcium and magnesium. Potential arrhythmic mechanisms of these substances, e.g. serotonin and high energy phosphates, include induction of coronary constriction, calcium overloading, and induction of delayed after-depolarizations. Alpha-granules produce thromboxanes and other arachidonic acid products with many potential arrhythmic effects mediated by interference with cardiac sodium, calcium and potassium channels. Alpha-granules also contain hundreds of proteins that could potentially serve as ligands to receptors on cardiomyocytes. Lysosomal products probably do not have an important arrhythmic effect. Platelet products and ischemia can induce coronary permeability, thereby enhancing interaction with surrounding cardiomyocytes. Antiplatelet therapy is known to improve survival after myocardial infarction. Although an important part of this effect results from prevention of coronary clot formation, there is evidence to suggest that antiplatelet therapy also induces anti-arrhythmic effects during ischemia by preventing the release of platelet activation products.

  17. Metoclopramide-induced cardiac arrest

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    Martha M. Rumore

    2011-11-01

    Full Text Available The authors report a case of cardiac arrest in a patient receiving intravenous (IV metoclopramide and review the pertinent literature. A 62-year-old morbidly obese female admitted for a gastric sleeve procedure, developed cardiac arrest within one minute of receiving metoclopramide 10 mg via slow intravenous (IV injection. Bradycardia at 4 beats/min immediately appeared, progressing rapidly to asystole. Chest compressions restored vital function. Electrocardiogram (ECG revealed ST depression indicative of myocardial injury. Following intubation, the patient was transferred to the intensive care unit. Various cardiac dysrrhythmias including supraventricular tachycardia (SVT associated with hypertension and atrial fibrillation occurred. Following IV esmolol and metoprolol, the patient reverted to normal sinus rhythm. Repeat ECGs revealed ST depression resolution without pre-admission changes. Metoclopramide is a non-specific dopamine receptor antagonist. Seven cases of cardiac arrest and one of sinus arrest with metoclopramide were found in the literature. The metoclopramide prescribing information does not list precautions or adverse drug reactions (ADRs related to cardiac arrest. The reaction is not dose related but may relate to the IV administration route. Coronary artery disease was the sole risk factor identified. According to Naranjo, the association was possible. Other reports of cardiac arrest, severe bradycardia, and SVT were reviewed. In one case, five separate IV doses of 10 mg metoclopramide were immediately followed by asystole repeatedly. The mechanism(s underlying metoclopramide’s cardiac arrest-inducing effects is unknown. Structural similarities to procainamide may play a role. In view of eight previous cases of cardiac arrest from metoclopramide having been reported, further elucidation of this ADR and patient monitoring is needed. Our report should alert clinicians to monitor patients and remain diligent in surveillance and

  18. [Electrophysiologic effects and arrhythmogenic potential of diphemanil methylsulfate on rabbit purkinje fibers. Correlations with clinical observations of QT prolongation in pediatrics].

    Science.gov (United States)

    Adamantidis, M; Dumotier, B; Caron, J; Dupuis, B

    1998-12-01

    Serious undesirable cardiac side effects have been reported with treatment with diphemanil methylsulfate (Prantal) in premature babies or neonates. To understand the origin of this problem, the authors undertook an electrophysiological study of the effects of this product in vitro on rabbit Purkinje fibres. In three separate series (N = 5 to N = 8), the effects of increasing concentrations (0.1 microM-30 microM) of diphemanil methylsulfate, different frequencies of stimulation (0.2 Hz, 1 Hz, 2 Hz) and duration of exposition (60 min followed by 120 min washout) were observed on the properties of the action potential. The results show a clearcut antiarrhythmic Class III type action characterised by a concentration-dependent prolongation of the action potential duration with an inverse frequency dependency without significant changes of the other parameters. During stimulation at 0.2 Hz, early post-depolarizations and induced activity were observed in 3/8 of the fibres exposed to 10 microM and 8/8 fibres exposed to 30 microM. The effect did not attain a steady state after 60 min of exposition. It was not reversed by 120 min of washout of the preparation. These results were compatible with the reported cardiac arrhythmic effects of prolongation of the QT interval and torsades de pointe. PMID:9891832

  19. Epigenetic regulation in cardiac fibrosis

    Institute of Scientific and Technical Information of China (English)

    Li-Ming; Yu; Yong; Xu

    2015-01-01

    Cardiac fibrosis represents an adoptive response in the heart exposed to various stress cues. While resolution of the fibrogenic response heralds normalization of heart function, persistent fibrogenesis is usually associated with progressive loss of heart function and eventually heart failure. Cardiac fibrosis is regulated by a myriad of factors that converge on the transcription of genes encoding extracellular matrix proteins, a process the epigenetic machinery plays a pivotal role. In this minireview, we summarize recent advances regarding the epigenetic regulation of cardiac fibrosis focusing on the role of histone and DNA modifications and non-coding RNAs.

  20. Cardiac perioperative complications in noncardiac surgery

    OpenAIRE

    Radovanović Dragana; Kolak Radmila; Stokić Aleksandar; Radovanović Zoran; Jovanović Gordana

    2008-01-01

    Anesthesiologists are confronted with an increasing population of patients undergoing noncardiac surgery who are at risk for cardiac complications in the perioperative period. Perioperative cardiac complications are responsible for significant mortality and morbidity. The aim of the present study was to determine the incidence of perioperative (operative and postoperative) cardiac complications and correlations between the incidence of perioperative cardiac complications and type of surgical ...

  1. Antiarrhythmic effect of growth factor-supplemented cardiac progenitor cells in chronic infarcted heart.

    Science.gov (United States)

    Savi, Monia; Bocchi, Leonardo; Rossi, Stefano; Frati, Caterina; Graiani, Gallia; Lagrasta, Costanza; Miragoli, Michele; Di Pasquale, Elisa; Stirparo, Giuliano G; Mastrototaro, Giuseppina; Urbanek, Konrad; De Angelis, Antonella; Macchi, Emilio; Stilli, Donatella; Quaini, Federico; Musso, Ezio

    2016-06-01

    c-Kit(pos) cardiac progenitor cells (CPCs) represent a successful approach in healing the infarcted heart and rescuing its mechanical function, but electrophysiological consequences are uncertain. CPC mobilization promoted by hepatocyte growth factor (HGF) and IGF-1 improved electrogenesis in myocardial infarction (MI). We hypothesized that locally delivered CPCs supplemented with HGF + IGF-1 (GFs) can concur in ameliorating electrical stability of the regenerated heart. Adult male Wistar rats (139 rats) with 4-wk-old MI or sham conditions were randomized to receive intramyocardial injection of GFs, CPCs, CPCs + GFs, or vehicle (V). Enhanced green fluorescent protein-tagged CPCs were used for cell tracking. Vulnerability to stress-induced arrhythmia was assessed by telemetry-ECG. Basic cardiac electrophysiological properties were examined by epicardial multiple-lead recording. Hemodynamic function was measured invasively. Hearts were subjected to anatomical, morphometric, immunohistochemical, and molecular biology analyses. Compared with V and at variance with individual CPCs, CPCs + GFs approximately halved arrhythmias in all animals, restoring cardiac anisotropy toward sham values. GFs alone reduced arrhythmias by less than CPCs + GFs, prolonging ventricular refractoriness without affecting conduction velocity. Concomitantly, CPCs + GFs reactivated the expression levels of Connexin-43 and Connexin-40 as well as channel proteins of key depolarizing and repolarizing ion currents differently than sole GFs. Mechanical function and anatomical remodeling were equally improved by all regenerative treatments, thus exhibiting a divergent behavior relative to electrical aspects. Conclusively, we provided evidence of distinctive antiarrhythmic action of locally injected GF-supplemented CPCs, likely attributable to retrieval of Connexin-43, Connexin-40, and Cav1.2 expression, favoring intercellular coupling and spread of excitation in mended heart.

  2. Microelectrode array recordings of cardiac action potentials as a high throughput method to evaluate pesticide toxicity.

    Science.gov (United States)

    Natarajan, A; Molnar, P; Sieverdes, K; Jamshidi, A; Hickman, J J

    2006-04-01

    The threat of environmental pollution, biological warfare agent dissemination and new diseases in recent decades has increased research into cell-based biosensors. The creation of this class of sensors could specifically aid the detection of toxic chemicals and their effects in the environment, such as pyrethroid pesticides. Pyrethroids are synthetic pesticides that have been used increasingly over the last decade to replace other pesticides like DDT. In this study we used a high-throughput method to detect pyrethroids by using multielectrode extracellular recordings from cardiac cells. The data from this cell-electrode hybrid system was compared to published results obtained with patch-clamp electrophysiology and also used as an alternative method to further understand pyrethroid effects. Our biosensor consisted of a confluent monolayer of cardiac myocytes cultured on microelectrode arrays (MEA) composed of 60 substrate-integrated electrodes. Spontaneous activity of these beating cells produced extracellular field potentials in the range of 100 microV to nearly 1200 microV with a beating frequency of 0.5-4 Hz. All of the tested pyrethroids; alpha-Cypermethrin, Tetramethrin and Tefluthrin, produced similar changes in the electrophysiological properties of the cardiac myocytes, namely reduced beating frequency and amplitude. The sensitivity of our toxin detection method was comparable to earlier patch-clamp studies, which indicates that, in specific applications, high-throughput extracellular methods can replace single-cell studies. Moreover, the similar effect of all three pyrethroids on the measured parameters suggests, that not only detection of the toxins but, their classification might also be possible with this method. Overall our results support the idea that whole cell biosensors might be viable alternatives when compared to current toxin detection methods. PMID:16198528

  3. 面向短 QT 综合征的电生理建模与仿真研究进展%Research Advance on the Electrophysiological Modeling and Simulation of Short QT Syndrome

    Institute of Scientific and Technical Information of China (English)

    罗存金; 王宽全; 袁永峰; 吕伟刚; Henggui Zhang

    2015-01-01

    近年来,多物理尺度建模仿真心电动力学研究已经取得了显著进展。本文介绍当前心脏建模仿真领域中心肌细胞钾离子通道基因突变引起短QT综合征的研究情况。首先从Denis Noble多物理尺度划分的角度介绍了亚细胞与细胞级模型、心肌纤维与组织级模型、心脏器官级模型以及仿真心电图等数学模型,并从量化的角度来分析短QT综合征基因变异在细胞、组织、器官等多层面上对心电功能的影响;然后重点列出了三种短QT综合征亚型近期的研究成果;最后进一步探讨了面向短QT综合征的电生理建模与仿真的研究方向和应用前景。%Multi-physical scale modeling for simulating the electrophysiological dynamics of the heart is rapidly evolving and has made significant progress in the last decade .In this paper ,we briefly review the current development of cardiac modeling field with a particular focus on the modeling of short QT (SQT )syndrome arising from gene mutations in cardiac potassium channels . Firstly ,we introduce Denis Noble’s definition on multi-physical scale modeling of cardiac systems at sub-cellular ,cellular ,tissue and whole organ levels .Secondly ,we describe quantities that have been used to characterize the functional impacts of SQT gene muta-tions on the electrical activity of cardiac systems at cellular ,tissue and whole organ levels .Then we review up-to-date research re-sults on quantifying the functional impacts of three SQT gene mutations associated with potassium channels on the genesis of cardiac arrhythmia that underlie cardiac sudden death .Finally we outline possible research and application prospects of the electrophysi-ological modeling and simulation of SQT syndrome in the future .

  4. THE CLINICAL AND NEURO-ELECTROPHYSIOLOGIC STUDY ON CORTICOBASAL DEGENERATION

    Institute of Scientific and Technical Information of China (English)

    LIU Qingrui; LI Fengluan; HAN Ying; GUO Liru

    2004-01-01

    Objective: To explore the clinical and neuroelectrophysiologic features of patients with cortical basal degeneration (CBD). Methods: Twenty-nine patients with clinical diagnosis of CBD were examined in detail in symptoms, sings, CT/MRI, SPECT and electrophysiology and compared with other diseases in clinical features. Results: The results showed that asymmetrical Parkinson′s manifestations were presented in all cases, cortical dysfunction in 23 cases (79.3%), other disorders in 11 cases (37.9%). Twenty-one cases showedasymmetrical atrophy in CT/MRI and 25 patients were hypoperfused in the fronto-parietal regions in SPECT and affected contralateral limbs. There were asymmetrical slow waves in 19 cases in EEG. In surface EMG, fifteen cases with myoclonus showed enhanced responses in their myoclonus arm or leg, cortical reflexes enhanced and with normal somatosensory evoked potential (SEP). Twenty-six patients showed normal CMCT in MEPs.Conclusion: CBD is characterized by a slow progressive disease with both cortical and basal ganglionic dysfunction. The most manifestation of CBD was asymmetric Parkinson′s s yndrome, cortical dysfunction and other movement disorders. Brain imaging showed fronto-parietal atrophy. The study of electrophysiology showed that cortical excitability enhanced and pyramidal tract was intact.%目的:探讨皮质基底节变性(CBD)患者的临床和神经电生理特征.方法:对29例临床诊断为CBD患者,系统分析其临床症状、体征、常规化验检查、脑CT/MRI、SPECT以及神经电生理改变,并与其它疾病相对比.结果:结果显示,29例患者均出现不对称性帕金森样表现,皮层功能受损占79.3%,其它功能障碍占37.9%.21例患者脑CT或MRI显示不对称性脑萎缩,SPECT显示额顶区低灌注表现,以受损肢体的功能区较明显.EEG显示19例患者出现不对称性慢波,伴有肌阵挛的15例病人,表面肌电图显示患肢随意运动时可诱发巨大电位,皮层反应增强

  5. Robot-assisted cardiac surgery.

    Science.gov (United States)

    Ishikawa, Norihiko; Watanabe, Go

    2015-01-01

    Recognition of the significant advantages of minimizing surgical trauma has resulted in the development of minimally invasive surgical procedures. Endoscopic surgery offers patients the benefits of minimally invasive surgery, and surgical robots have enhanced the ability and precision of surgeons. Consequently, technological advances have facilitated totally endoscopic robotic cardiac surgery, which has allowed surgeons to operate endoscopically rather than through a median sternotomy during cardiac surgery. Thus, repairs for structural heart conditions, including mitral valve plasty, atrial septal defect closure, multivessel minimally invasive direct coronary artery bypass grafting (MIDCAB), and totally endoscopic coronary artery bypass graft surgery (CABG), can be totally endoscopic. Robot-assisted cardiac surgery as minimally invasive cardiac surgery is reviewed. PMID:26134073

  6. Recent developments in cardiac pacing.

    Science.gov (United States)

    Rodak, D J

    1995-10-01

    Indications for cardiac pacing continue to expand. Pacing to improve functional capacity, which is now common, relies on careful patient selection and technical improvements, such as complex software algorithms and diagnostic capabilities.

  7. Robotic Applications in Cardiac Surgery

    Directory of Open Access Journals (Sweden)

    Alan P. Kypson

    2008-11-01

    Full Text Available Traditionally, cardiac surgery has been performed through a median sternotomy, which allows the surgeon generous access to the heart and surrounding great vessels. As a paradigm shift in the size and location of incisions occurs in cardiac surgery, new methods have been developed to allow the surgeon the same amount of dexterity and accessibility to the heart in confined spaces and in a less invasive manner. Initially, long instruments without pivot points were used, however, more recent robotic telemanipulation systems have been applied that allow for improved dexterity, enabling the surgeon to perform cardiac surgery from a distance not previously possible. In this rapidly evolving field, we review the recent history and clinical results of using robotics in cardiac surgery.

  8. Dynamic BOLD functional connectivity in humans and its electrophysiological correlates.

    Science.gov (United States)

    Tagliazucchi, Enzo; von Wegner, Frederic; Morzelewski, Astrid; Brodbeck, Verena; Laufs, Helmut

    2012-01-01

    Neural oscillations subserve many human perceptual and cognitive operations. Accordingly, brain functional connectivity is not static in time, but fluctuates dynamically following the synchronization and desynchronization of neural populations. This dynamic functional connectivity has recently been demonstrated in spontaneous fluctuations of the Blood Oxygen Level-Dependent (BOLD) signal, measured with functional Magnetic Resonance Imaging (fMRI). We analyzed temporal fluctuations in BOLD connectivity and their electrophysiological correlates, by means of long (≈50 min) joint electroencephalographic (EEG) and fMRI recordings obtained from two populations: 15 awake subjects and 13 subjects undergoing vigilance transitions. We identified positive and negative correlations between EEG spectral power (extracted from electrodes covering different scalp regions) and fMRI BOLD connectivity in a network of 90 cortical and subcortical regions (with millimeter spatial resolution). In particular, increased alpha (8-12 Hz) and beta (15-30 Hz) power were related to decreased functional connectivity, whereas gamma (30-60 Hz) power correlated positively with BOLD connectivity between specific brain regions. These patterns were altered for subjects undergoing vigilance changes, with slower oscillations being correlated with functional connectivity increases. Dynamic BOLD functional connectivity was reflected in the fluctuations of graph theoretical indices of network structure, with changes in frontal and central alpha power correlating with average path length. Our results strongly suggest that fluctuations of BOLD functional connectivity have a neurophysiological origin. Positive correlations with gamma can be interpreted as facilitating increased BOLD connectivity needed to integrate brain regions for cognitive performance. Negative correlations with alpha suggest a temporary functional weakening of local and long-range connectivity, associated with an idling state. PMID

  9. Dynamic BOLD functional connectivity in humans and its electrophysiological correlates

    Directory of Open Access Journals (Sweden)

    Enzo eTagliazucchi

    2012-12-01

    Full Text Available Neural oscillations subserve many human perceptual and cognitive operations. Accordingly, brain functional connectivity is not static in time, but fluctuates dynamically following the synchronization and desynchronization of neural populations. This dynamic functional connectivity has recently been demonstrated in spontaneous fluctuations of the Blood Oxygen Level-Dependent (BOLD signal, measured with functional Magnetic Resonance Imaging (fMRI. We analyzed temporal fluctuations in BOLD connectivity and their electrophysiological correlates, by means of long (approx. 50 min joint electroencephalographic (EEG and fMRI recordings obtained from two populations: 15 awake subjects and 13 subjects undergoing vigilance transitions.We identified positive and negative correlations between EEG spectral power (extracted from electrodes covering different scalp regions and fMRI BOLD connectivity in a network of 90 cortical and subcortical regions (with millimeter spatial resolution. In particular, increased alpha (8-12 Hz and beta (15-30 Hz power were related to decreased functional connectivity, whereas gamma (30-60 Hz power correlated positively with BOLD connectivity between specific brain regions. These patterns were altered for subjects undergoing vigilance changes, with slower oscillations being correlated with functional connectivity increases. Dynamic BOLD functional connectivity was reflected in the fluctuations of graph theoretical indices of network structure, with changes in frontal and central alpha power correlating with average path length.Our results strongly suggest that fluctuations of BOLD functional connectivity have a neurophysiological origin. Positive correlations with gamma can be interpreted as facilitating increased BOLD connectivity needed to integrate brain regions for cognitive performance. Negative correlations with alpha suggest a temporary functional weakening of local and long-range connectivity, associated with an idling

  10. [Characteristics of general anesthesia in the investigation of heart electrophysiology].

    Science.gov (United States)

    Narbutas, Kestutis; Lekas, Raimundas; Rimkiene, Aldona; Civinskiene, Genuvaite

    2002-01-01

    Investigating electrophysiological properties of the heart under acute experimental conditions, dogs are affected by operative stress because of traumatic surgical manipulations, so investigations are performed under general anaesthesia. Many anaesthetics together with their main function have desintegrating influence on autonomic regulation mechanisms. That is why anaesthetics used during experiments must fullfil such requirement--have minimal influence on autonomic nervous system (ANS) and heart conductivity system (HCS) interaction parameters or to make this influence insignificant. We did not found common anaesthesia methodics that can fullfil that requirements, so we decided to prepare new common anaesthesia methodics, which could fullfil requirements mentioned above. We choose medicaments according to their pharmacokinetics and pharmacodynamics action. For methodics optimization we've used 2 groups of dogs (mongrel dogs males weight 7-15 kg) (n = 10). We've applied different anaesthesia schemas on each group. Premedication in the I-st group was performed with intramuscle (i.m.) combination of diazepam, ketamine and phentanyl and for anaesthesia continuous intravenous (i.v.) infusion of thiopental and ketamine. In II-nd group premedication was performed with i.m. injection of ketamine/phentanyl combination and for anaesthesia--continuous i.v. infusion of thiopental. Induction in both groups was performed with i.v. thiopental injection. Suitability of premedication and anaesthesia was valued by adequativity of haemodynamics (heart rate 1/min) and surgical manipulations during experiments. Our conclusion is: investigating interaction of ANS and HCS methodics used in the I-st group of dogs is more suitable. PMID:12474758

  11. Electrophysiologic changes in patients with untreated primary hypothyroidism.

    Science.gov (United States)

    Eslamian, Fariba; Bahrami, Amir; Aghamohammadzadeh, Naser; Niafar, Mitra; Salekzamani, Yaghoub; Behkamrad, Keyvan

    2011-06-01

    Thyroid diseases may cause signs and symptoms of neuromuscular dysfunction. Hypothyroidism has been associated with the clinical features of proximal muscle weakness, mononeuropathy, and sensorimotor polyneuropathy. This study aimed at evaluating the electrophysiologic findings in patients with untreated spontaneous hypothyroidism and comparing them with a healthy control group. In a case-control cross-sectional study, 40 patients with definite diagnosis of clinical hypothyroidism and 40 healthy control subjects were evaluated by electromyography and nerve conduction studies in the specialized clinic of the Tabriz University of Medical Sciences during an 18-month period. Seven male and 33 female patients with a mean age of 39.5 ± 11.8 years were enrolled. In this group, there were 12 cases (30%) with clinical muscle weakness, with severity of approximately 4/5, 18 cases (45%) with decreased or absent deep tendon reflexes, 6 cases (15%) with neuropathy, including 4 sensory and 2 sensorimotor, of which 5 cases were mild and 1 case was moderate, 3 cases (7.5%) with myopathy, and 13 cases (32.5%) with carpal tunnel syndrome, which was mild in 7, moderate in 10, and severe in 2 hands. Patients with neuropathy were significantly older than those without neuropathy (P = 0.001). There was no significant relation between gender, duration of the disease, serum TSH level, and the presence of clinical muscle weakness with the occurrence of neuropathy or myopathy. Female gender, increasing age, duration of the disease, and the frequency of clinical weakness were, however, significantly related to the presence of carpal tunnel syndrome (P < 0.05). In conclusion, in patients with untreated primary hypothyroidism, majority had the carpal tunnel syndrome. Mild neuropathy mainly of sensory type and myopathy were uncommon and rare findings, respectively. Early treatment would hinder the progression of mentioned abnormalities and minimize their occurrence. PMID:21633261

  12. Visual adaptation provides objective electrophysiological evidence of facial identity discrimination.

    Science.gov (United States)

    Retter, Talia L; Rossion, Bruno

    2016-07-01

    Discrimination of facial identities is a fundamental function of the human brain that is challenging to examine with macroscopic measurements of neural activity, such as those obtained with functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). Although visual adaptation or repetition suppression (RS) stimulation paradigms have been successfully implemented to this end with such recording techniques, objective evidence of an identity-specific discrimination response due to adaptation at the level of the visual representation is lacking. Here, we addressed this issue with fast periodic visual stimulation (FPVS) and EEG recording combined with a symmetry/asymmetry adaptation paradigm. Adaptation to one facial identity is induced through repeated presentation of that identity at a rate of 6 images per second (6 Hz) over 10 sec. Subsequently, this identity is presented in alternation with another facial identity (i.e., its anti-face, both faces being equidistant from an average face), producing an identity repetition rate of 3 Hz over a 20 sec testing sequence. A clear EEG response at 3 Hz is observed over the right occipito-temporal (ROT) cortex, indexing discrimination between the two facial identities in the absence of an explicit behavioral discrimination measure. This face identity discrimination occurs immediately after adaptation and disappears rapidly within 20 sec. Importantly, this 3 Hz response is not observed in a control condition without the single-identity 10 sec adaptation period. These results indicate that visual adaptation to a given facial identity produces an objective (i.e., at a pre-defined stimulation frequency) electrophysiological index of visual discrimination between that identity and another, and provides a unique behavior-free quantification of the effect of visual adaptation.

  13. Electrophysiological effects of trace amines on mesencephalic dopaminergic neurons

    Directory of Open Access Journals (Sweden)

    Ada eLedonne

    2011-07-01

    Full Text Available Trace amines (TAs are a class of endogenous compounds strictly related to classic monoamine neurotransmitters with regard to their structure, metabolism and tissue distribution. Although the presence of TAs in mammalian brain has been recognized for decades, until recently they were considered to be by-products of amino acid metabolism or as ‘false’ neurotransmitters. The discovery in 2001 of a new family of G protein-coupled receptors (GPCRs, namely trace amines receptors, has re-ignited interest in TAs. In particular, two members of the family, trace amine receptor 1 (TA1 and trace amine receptor 2 (TA2, were shown to be highly sensitive to these endogenous compounds. Experimental evidence suggests that TAs modulate the activity of catecholaminergic neurons and that TA dysregulation may contribute to neuropsychiatric disorders, including schizophrenia, attention deficit hyperactivity disorder, depression and Parkinson’s disease, all of which are characterised by altered monoaminergic networks. Here we review recent data concerning the electrophysiological effects of TAs on the activity of mesencephalic dopaminergic neurons. In the context of recent data obtained with TA1 receptor knockout mice, we also discuss the mechanisms by which the activation of these receptors modulates the activity of these neurons. Three important new aspects of TAs action have recently emerged: (a inhibition of firing due to increased release of dopamine; (b reduction of D2 and GABAB receptor-mediated inhibitory responses (excitatory effects due to dysinhibition; and (c a direct TA1 receptor-mediated activation of GIRK channels which produce cell membrane hyperpolarization. While the first two effects have been well documented in our laboratory, the direct activation of GIRK channels by TA1 receptors has been reported by others, but has not been seen in our laboratory (Geracitano et al., 2004. Further research is needed to address this point, and to further

  14. Electrophysiological and Anatomical Correlates of Spinal Cord Optical Coherence Tomography.

    Science.gov (United States)

    Giardini, Mario E; Zippo, Antonio G; Valente, Maurizio; Krstajic, Nikola; Biella, Gabriele E M

    2016-01-01

    Despite the continuous improvement in medical imaging technology, visualizing the spinal cord poses severe problems due to structural or incidental causes, such as small access space and motion artifacts. In addition, positional guidance on the spinal cord is not commonly available during surgery, with the exception of neuronavigation techniques based on static pre-surgical data and of radiation-based methods, such as fluoroscopy. A fast, bedside, intraoperative real-time imaging, particularly necessary during the positioning of endoscopic probes or tools, is an unsolved issue. The objective of our work, performed on experimental rats, is to demonstrate potential intraoperative spinal cord imaging and probe guidance by optical coherence tomography (OCT). Concurrently, we aimed to demonstrate that the electromagnetic OCT irradiation exerted no particular effect at the neuronal and synaptic levels. OCT is a user-friendly, low-cost and endoscopy-compatible photonics-based imaging technique. In particular, by using a Fourier-domain OCT imager, operating at 850 nm wavelength and scanning transversally with respect to the spinal cord, we have been able to: 1) accurately image tissue structures in an animal model (muscle, spine bone, cerebro-spinal fluid, dura mater and spinal cord), and 2) identify the position of a recording microelectrode approaching and inserting into the cord tissue 3) check that the infrared radiation has no actual effect on the electrophysiological activity of spinal neurons. The technique, potentially extendable to full three-dimensional image reconstruction, shows prospective further application not only in endoscopic intraoperative analyses and for probe insertion guidance, but also in emergency and adverse situations (e.g. after trauma) for damage recognition, diagnosis and fast image-guided intervention. PMID:27050096

  15. Clinical and Electrophysiological Report of a Unilateral Retinitis Pigmentosa Case

    Directory of Open Access Journals (Sweden)

    Sedaghat MR

    2014-04-01

    Full Text Available Introduction: To describe clinical and electrophysiological features of a patient with unilateral Retinitis Pigmentosa (RP. Case: A 29-year-old female with a long history of progressive visual disturbance in the right eye has undergone multiple eye examinations during the past eight years. There was nothing noticeable in her past medical and ocular history. Comprehensive eye examinations were done in the first visit. All data was suggestive of right eye RP. Posterior segment fundal examination findings were: a pallor waxy disc, vessel attenuation, and extended pigmentary degeneration of the mid-peripheral retina. The left eye examination was normal. Comparing the automated 60 degree and 30 degree visual fields of both eyes obviously showed significant defects in the right eye visual field but normal in the left eye.  All of the probable infectious agents, which can cause similar ocular manifestations, were ruled out by serological tests. The standard photopic and scotopic electroretinographies were significantly reduced in amplitude in the right eye; however, they were normal in the left eye. Also, the standard Electro-Oculography (EOG results were the same as the Electro-Retinography (ERG ones in both eyes. Eye examinations were normal in other family members. Over an eight-year follow-up period, progressive deteriorating vision has gradually become more noticeable in the right eye. The left eye has been completely normal since.  This data was compatible with the Francois and Verriesr unilateral RP diagnostic criteria. Conclusion: Clinical signs and symptoms, a minimum of a five-year follow-up period, and confirmatory ERG and EOG are very helpful to diagnose andaffirm the case of unilateral RP.

  16. Cardiac Biomarkers in Hyperthyroid Cats

    OpenAIRE

    Sangster, Jodi Kirsten

    2013-01-01

    Background: Hyperthyroidism has substantial effects on the circulatory system. The cardiac biomarkers NT-proBNP and troponin I (cTNI) have proven useful in identifying cats with myocardial disease but have not been as extensively investigated in hyperthyroidism.Hypothesis: Plasma NT-proBNP and cTNI concentrations are higher in cats with primary cardiac disease than in cats with hyperthyroidism and higher in cats with hyperthyroidism than in healthy control cats.Animals: Twenty-three hyperthyr...

  17. Cardiac manifestations in systemic sclerosis

    Institute of Scientific and Technical Information of China (English)

    Sevdalina; Lambova

    2014-01-01

    Primary cardiac involvement, which develops as a direct consequence of systemic sclerosis(SSc), may manifest as myocardial damage, fibrosis of the conduction system, pericardial and, less frequently, as valvular disease. In addition, cardiac complications in SSc may develop as a secondary phenomenon due to pulmonary arterial hypertension and kidney pathology. The prevalence of primary cardiac involvement in SSc is variable and difficult to determine because of the diversity of cardiac manifestations, the presence of subclinical periods, the type of diagnostic tools applied, and the diversity of patient populations. When clinically manifested, cardiac involvement is thought to be an important prognostic factor. Profound microvascular disease is a pathognomonic feature of SSc, as both vasospasm and structural alterations are present. Such alterations are thought to predict macrovascular atherosclerosis over time. There are contradictory reports regarding the prevalence of atherosclerosis in SSc. According to some authors, the prevalence of atherosclerosis of the large epicardial coronary arteries is similar to that of the general population, in contrast with other rheumatic diseases such as rheumatoid arthritis and systemic lupus erythematosus. However, the level of inflammation in SSc is inferior. Thus, the atherosclerotic process may not be as aggressive and not easily detectable in smaller studies. Echocardiography(especially tissue Doppler imaging), single-photon emission computed tomography, magnetic resonance imaging and cardiac computed tomography are sensitive techniques for earlier detection of both structural and functional scleroderma-related cardiac pathologies. Screening for subclinical cardiac involvement via modern, sensitive tools provides an opportunity for early diagnosis and treatment, which is of crucial importance for a positive outcome.

  18. Computational Modeling of Cardiac Electromechanics

    OpenAIRE

    Krishnamoorthi, Shankarjee

    2013-01-01

    Cardiac arrhythmias are a leading cause of death worldwide. Notably, the electrophysiologiy and microstructural requirements for a fatal ventricular arrhythmia remain incompletely understood, thereby the treatment remains largely empirical. Standard antiarrhythmic drug therapy has failed to reduce, and in some instances has increased, the incidence of Sudden Cardiac Death (SCD). Hence, a more complete understanding of the mechanisms that foment a fatal arrhythmia is needed and computational m...

  19. Current trends in cardiac rehabilitation

    OpenAIRE

    Dafoe, W; Huston, P

    1997-01-01

    Cardiac rehabilitation can reduce mortality and morbidity for patients with many types of cardiac disease cost-effectively, yet is generally underutilized. Rehabilitation is helpful not only for patients who have had a myocardial infarction but also for those with stable angina or congestive heart failure or those who have undergone myocardial revascularization procedures, a heart transplant or heart valve surgery. The beneficial effects of rehabilitation include a reduction in the rate of de...

  20. An overview of cardiac morphogenesis.

    OpenAIRE

    Schleich, Jean-Marc; Abdulla, Tariq; Summers, Ron; Houyel, Lucile

    2013-01-01

    International audience Accurate knowledge of normal cardiac development is essential for properly understanding the morphogenesis of congenital cardiac malformations that represent the most common congenital anomaly in newborns. The heart is the first organ to function during embryonic development and is fully formed at 8 weeks of gestation. Recent studies stemming from molecular genetics have allowed specification of the role of cellular precursors in the field of heart development. In th...

  1. Physiological and pathological cardiac hypertrophy.

    Science.gov (United States)

    Shimizu, Ippei; Minamino, Tohru

    2016-08-01

    The heart must continuously pump blood to supply the body with oxygen and nutrients. To maintain the high energy consumption required by this role, the heart is equipped with multiple complex biological systems that allow adaptation to changes of systemic demand. The processes of growth (hypertrophy), angiogenesis, and metabolic plasticity are critically involved in maintenance of cardiac homeostasis. Cardiac hypertrophy is classified as physiological when it is associated with normal cardiac function or as pathological when associated with cardiac dysfunction. Physiological hypertrophy of the heart occurs in response to normal growth of children or during pregnancy, as well as in athletes. In contrast, pathological hypertrophy is induced by factors such as prolonged and abnormal hemodynamic stress, due to hypertension, myocardial infarction etc. Pathological hypertrophy is associated with fibrosis, capillary rarefaction, increased production of pro-inflammatory cytokines, and cellular dysfunction (impairment of signaling, suppression of autophagy, and abnormal cardiomyocyte/non-cardiomyocyte interactions), as well as undesirable epigenetic changes, with these complex responses leading to maladaptive cardiac remodeling and heart failure. This review describes the key molecules and cellular responses involved in physiological/pathological cardiac hypertrophy. PMID:27262674

  2. FGF21 and cardiac physiopathology

    Directory of Open Access Journals (Sweden)

    Anna ePlanavila

    2015-08-01

    Full Text Available The heart is not traditionally considered either a target or a site of fibroblast growth factor-21 (FGF21 production. However, recent findings indicate that FGF21 can act as a cardiomyokine; that is, it is produced by cardiac cells at significant levels and acts in an autocrine manner on the heart itself. The heart is sensitive to the effects of FGF21, both systemic and locally generated, owing to the expression in cardiomyocytes of β-Klotho, the key co-receptor known to confer specific responsiveness to FGF21 action. FGF21 has been demonstrated to protect against cardiac hypertrophy, cardiac inflammation, and oxidative stress. FGF21 expression in the heart is induced in response to cardiac insults, such as experimental cardiac hypertrophy and myocardial infarction in rodents, as well as in failing human hearts. Intracellular mechanisms involving PPARα and Sirt1 mediate transcriptional regulation of the FGF21 gene in response to exogenous stimuli. In humans, circulating FGF21 levels are elevated in coronary heart disease and atherosclerosis, and are associated with a higher risk of cardiovascular events in patients with type 2 diabetes. These findings provide new insights into the role of FGF21 in the heart and may offer potential therapeutic strategies for cardiac disease.

  3. [Stem cells and cardiac regeneration].

    Science.gov (United States)

    Perez Millan, Maria Ines; Lorenti, Alicia

    2006-01-01

    Stem cells are defined by virtue of their functional attributes: absence of tissue specific differentitated markers, capable of proliferation, able to self-maintain the population, able to produce a large number of differentiated, functional progeny, able to regenerate the tissue after injury. Cell therapy is an alternative for the treatment of several diseases, like cardiac diseases (cell cardiomyoplasty). A variety of stem cells could be used for cardiac repair: from cardiac and extracardiac sources. Each cell type has its own profile of advantages, limitations, and practicability issues in specific clinical settings. Differentiation of bone marrow stem cells to cardiomyocyte-like cells have been observed under different culture conditions. The presence of resident cardiac stem cell population capable of differentiation into cardiomyocyte or vascular lineage suggests that these cells could be used for cardiac tissue repair, and represent a great promise for clinical application. Stem cells mobilization by cytokines may also offer a strategy for cardiac regeneration. The use of stem cells (embryonic and adult) may hold the key to replacing cells lost in many devastating diseases. This potential benefit is a major focus for stem cell research.

  4. Cardiac Regeneration and Stem Cells.

    Science.gov (United States)

    Zhang, Yiqiang; Mignone, John; MacLellan, W Robb

    2015-10-01

    After decades of believing the heart loses the ability to regenerate soon after birth, numerous studies are now reporting that the adult heart may indeed be capable of regeneration, although the magnitude of new cardiac myocyte formation varies greatly. While this debate has energized the field of cardiac regeneration and led to a dramatic increase in our understanding of cardiac growth and repair, it has left much confusion in the field as to the prospects of regenerating the heart. Studies applying modern techniques of genetic lineage tracing and carbon-14 dating have begun to establish limits on the amount of endogenous regeneration after cardiac injury, but the underlying cellular mechanisms of this regeneration remained unclear. These same studies have also revealed an astonishing capacity for cardiac repair early in life that is largely lost with adult differentiation and maturation. Regardless, this renewed focus on cardiac regeneration as a therapeutic goal holds great promise as a novel strategy to address the leading cause of death in the developed world.

  5. Cardiac involvement in myotonic dystrophy

    DEFF Research Database (Denmark)

    Lund, Marie; Diaz, Lars Jorge; Ranthe, Mattis Flyvholm;

    2014-01-01

    genetic testing for DM1. Information on incident cardiac diseases was obtained from the NPR. We estimated standardized incidence ratios (SIRs) of cardiac disease compared with the background population, overall and according to selected diagnostic subgroups (cardiomyopathy, heart failure, conduction...... disorders, arrhythmias, and device implantation). In the DM cohort, SIR for any cardiac disease was 3.42 [95% confidence interval (CI) 3.01-3.86]; for a cardiac disease belonging to the selected subgroups 6.91 (95% CI: 5.93-8.01) and for other cardiac disease 2.59 (95% CI: 2.03-3.25). For a cardiac disease...... belonging to the selected subgroups, the risk was particularly high in the first year after DM diagnosis [SIR 15.4 (95% CI: 10.9-21.3)] but remained significantly elevated in subsequent years [SIR 6.07 (95% CI: 5.11-7.16]). The risk was higher in young cohort members [e.g. 20-39 years: SIR 18.1 (95% CI: 12...

  6. Cardiac imaging. A multimodality approach

    Energy Technology Data Exchange (ETDEWEB)

    Thelen, Manfred [Johannes Gutenberg University Hospital, Mainz (Germany); Erbel, Raimund [University Hospital Essen (Germany). Dept. of Cardiology; Kreitner, Karl-Friedrich [Johannes Gutenberg University Hospital, Mainz (Germany). Clinic and Polyclinic for Diagnostic and Interventional Radiology; Barkhausen, Joerg (eds.) [University Hospital Schleswig-Holstein, Luebeck (Germany). Dept. of Radiology and Nuclear Medicine

    2009-07-01

    An excellent atlas on modern diagnostic imaging of the heart Written by an interdisciplinary team of experts, Cardiac Imaging: A Multimodality Approach features an in-depth introduction to all current imaging modalities for the diagnostic assessment of the heart as well as a clinical overview of cardiac diseases and main indications for cardiac imaging. With a particular emphasis on CT and MRI, the first part of the atlas also covers conventional radiography, echocardiography, angiography and nuclear medicine imaging. Leading specialists demonstrate the latest advances in the field, and compare the strengths and weaknesses of each modality. The book's second part features clinical chapters on heart defects, endocarditis, coronary heart disease, cardiomyopathies, myocarditis, cardiac tumors, pericardial diseases, pulmonary vascular diseases, and diseases of the thoracic aorta. The authors address anatomy, pathophysiology, and clinical features, and evaluate the various diagnostic options. Key features: - Highly regarded experts in cardiology and radiology off er image-based teaching of the latest techniques - Readers learn how to decide which modality to use for which indication - Visually highlighted tables and essential points allow for easy navigation through the text - More than 600 outstanding images show up-to-date technology and current imaging protocols Cardiac Imaging: A Multimodality Approach is a must-have desk reference for cardiologists and radiologists in practice, as well as a study guide for residents in both fields. It will also appeal to cardiac surgeons, general practitioners, and medical physicists with a special interest in imaging of the heart. (orig.)

  7. Electrophysiological characterization of a large set of novel variants in the SCN5A-gene: identification of novel LQTS3 and BrS mutations.

    Science.gov (United States)

    Ortiz-Bonnin, Beatriz; Rinné, Susanne; Moss, Robin; Streit, Anne K; Scharf, Michael; Richter, Katrin; Stöber, Anika; Pfeufer, Arne; Seemann, Gunnar; Kääb, Stefan; Beckmann, Britt-Maria; Decher, Niels

    2016-08-01

    SCN5A encodes for the α-subunit of the cardiac voltage-gated sodium channel Nav1.5. Gain-of-function mutations in SCN5A are related to congenital long QT syndrome (LQTS3) characterized by delayed cardiac repolarization, leading to a prolonged QT interval in the ECG. Loss-of-function mutations in SCN5A are related to Brugada syndrome (BrS), characterized by an ST-segment elevation in the right precordial leads (V1-V3). The aim of this study was the characterization of a large set of novel SCN5A variants found in patients with different cardiac phenotypes, mainly LQTS and BrS. SCN5A variants of 13 families were functionally characterized in Xenopus laevis oocytes using the two-electrode voltage-clamp technique. We found in most of the cases, but not all, that the electrophysiology of the variants correlated with the clinically diagnosed phenotype. A susceptibility to develop LQTS can be suggested in patients carrying the variants S216L, K480N, A572D, F816Y, and G983D. However, taking the phenotype into account, the presence of the variants in genomic data bases, the mutational segregation, combined with our in vitro and in silico experiments, the variants S216L, S262G, K480N, A572D, F816Y, G983D, and T1526P remain as variants of unknown significance. However, the SCN5A variants R568H and A993T can be classified as pathogenic LQTS3 causing mutations, while R222stop and R2012H are novel BrS causing mutations. PMID:27287068

  8. Risk factors and the effect of cardiac resynchronization therapy on cardiac and non-cardiac mortality in MADIT-CRT

    DEFF Research Database (Denmark)

    Perkiomaki, Juha S; Ruwald, Anne-Christine; Kutyifa, Valentina;

    2015-01-01

    causes, 108 (63.9%) deemed cardiac, and 61 (36.1%) non-cardiac. In multivariate analysis, increased baseline creatinine was significantly associated with both cardiac and non-cardiac deaths [hazard ratio (HR) 2.97, P ...AIMS: To understand modes of death and factors associated with the risk for cardiac and non-cardiac deaths in patients with cardiac resynchronization therapy with implantable cardioverter-defibrillator (CRT-D) vs. implantable cardioverter-defibrillator (ICD) therapy, which may help clarify...... the action and limitations of cardiac resynchronization therapy (CRT) in relieving myocardial dysfunction. METHODS AND RESULTS: In Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy (MADIT-CRT), during 4 years of follow-up, 169 (9.3%) of 1820 patients died of known...

  9. Cardiac output during exercise

    DEFF Research Database (Denmark)

    Siebenmann, C; Rasmussen, P.; Sørensen, H.;

    2015-01-01

    Several techniques assessing cardiac output (Q) during exercise are available. The extent to which the measurements obtained from each respective technique compares to one another, however, is unclear. We quantified Q simultaneously using four methods: the Fick method with blood obtained from...... the right atrium (Q(Fick-M)), Innocor (inert gas rebreathing; Q(Inn)), Physioflow (impedance cardiography; Q(Phys)), and Nexfin (pulse contour analysis; Q(Pulse)) in 12 male subjects during incremental cycling exercise to exhaustion in normoxia and hypoxia (FiO2  = 12%). While all four methods reported...... a progressive increase in Q with exercise intensity, the slopes of the Q/oxygen uptake (VO2) relationship differed by up to 50% between methods in both normoxia [4.9 ± 0.3, 3.9 ± 0.2, 6.0 ± 0.4, 4.8 ± 0.2 L/min per L/min (mean ± SE) for Q(Fick-M), Q(Inn), QP hys and Q(Pulse), respectively; P = 0...

  10. The emerging role of in vitro electrophysiological methods in CNS safety pharmacology.

    Science.gov (United States)

    Accardi, Michael V; Pugsley, Michael K; Forster, Roy; Troncy, Eric; Huang, Hai; Authier, Simon

    2016-01-01

    Adverse CNS effects account for a sizeable proportion of all drug attrition cases. These adverse CNS effects are mediated predominately by off-target drug activity on neuronal ion-channels, receptors, transporters and enzymes - altering neuronal function and network communication. In response to these concerns, there is growing support within the pharmaceutical industry for the requirement to perform more comprehensive CNS safety testing prior to first-in-human trials. Accordingly, CNS safety pharmacology commonly integrates several in vitro assay methods for screening neuronal targets in order to properly assess therapeutic safety. One essential assay method is the in vitro electrophysiological technique - the 'gold standard' ion channel assay. The in vitro electrophysiological method is a useful technique, amenable to a variety of different tissues and cell configurations, capable of assessing minute changes in ion channel activity from the level of a single receptor to a complex neuronal network. Recent advances in automated technology have further expanded the usefulness of in vitro electrophysiological methods into the realm of high-throughput, addressing the bottleneck imposed by the manual conduct of the technique. However, despite a large range of applications, manual and automated in vitro electrophysiological techniques have had a slow penetrance into the field of safety pharmacology. Nevertheless, developments in throughput capabilities and in vivo applicability have led to a renewed interest in in vitro electrophysiological techniques that, when complimented by more traditional safety pharmacology methods, often increase the preclinical predictability of potential CNS liabilities.

  11. Electrophysiological Motor Unit Number Estimation (MUNE) Measuring Compound Muscle Action Potential (CMAP) in Mouse Hindlimb Muscles.

    Science.gov (United States)

    Arnold, W David; Sheth, Kajri A; Wier, Christopher G; Kissel, John T; Burghes, Arthur H; Kolb, Stephen J

    2015-01-01

    Compound muscle action potential (CMAP) and motor unit number estimation (MUNE) are electrophysiological techniques that can be used to monitor the functional status of a motor unit pool in vivo. These measures can provide insight into the normal development and degeneration of the neuromuscular system. These measures have clear translational potential because they are routinely applied in diagnostic and clinical human studies. We present electrophysiological techniques similar to those employed in humans to allow recordings of mouse sciatic nerve function. The CMAP response represents the electrophysiological output from a muscle or group of muscles following supramaximal stimulation of a peripheral nerve. MUNE is an electrophysiological technique that is based on modifications of the CMAP response. MUNE is a calculated value that represents the estimated number of motor neurons or axons (motor control input) supplying the muscle or group of muscles being tested. We present methods for recording CMAP responses from the proximal leg muscles using surface recording electrodes following the stimulation of the sciatic nerve in mice. An incremental MUNE technique is described using submaximal stimuli to determine the average single motor unit potential (SMUP) size. MUNE is calculated by dividing the CMAP amplitude (peak-to-peak) by the SMUP amplitude (peak-to-peak). These electrophysiological techniques allow repeated measures in both neonatal and adult mice in such a manner that facilitates rapid analysis and data collection while reducing the number of animals required for experimental testing. Furthermore, these measures are similar to those recorded in human studies allowing more direct comparisons. PMID:26436455

  12. Denervation syndromes of the shoulder girdle: MR imaging with electrophysiologic correlation

    International Nuclear Information System (INIS)

    Objective. To investigate the use of MR imaging in the characterization of denervated muscle of the shoulder correlated with electrophysiologic studies.Design and patients. We studied with MR imaging five patients who presented with shoulder weakness and pain and who underwent electrophysiologic studies. On MR imaging the distribution of muscle edema and fatty infiltration was recorded, as was the presence of masses impinging on a regional nerve.Results. Acute/subacute denervation was best seen on T2-weighted fast spin-echo images with fat saturation, showing increased SI related to neurogenic edema. Chronic denervation was best seen on T1-weighted spin-echo images, demonstrating loss of muscle bulk and diffuse areas of increased signal intensity within the muscle. Three patients showed MR imaging and electrophysiologic findings of Parsonage Turner syndrome. One patient demonstrated an arteriovenous malformation within the spinoglenoid notch, impinging on the suprascapular nerve with associated atrophy of the infraspinatus muscle. The fifth patient demonstrated fatty atrophy of the teres minor muscle caused by compression by a cyst of the axillary nerve and electrophysiologic findings of an incomplete axillary nerve block.Conclusion. MR imaging is useful in detecting and characterizing denervation atrophy and neurogenic edema in shoulder muscles. MR imaging can provide additional information to electrophysiologic studies by estimating the age (acute/chronic) and identifying morphologic causes for shoulder pain and atrophy. (orig.)

  13. HDAC Inhibition Modulates Cardiac PPARs and Fatty Acid Metabolism in Diabetic Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Ting-I Lee

    2016-01-01

    Full Text Available Peroxisome proliferator-activated receptors (PPARs regulate cardiac glucose and lipid homeostasis. Histone deacetylase (HDAC inhibitor has anti-inflammatory effects which may play a key role in modulating PPARs and fatty acid metabolism. The aim of this study was to investigate whether HDAC inhibitor, MPT0E014, can modulate myocardial PPARs, inflammation, and fatty acid metabolism in diabetes mellitus (DM cardiomyopathy. Electrocardiography, echocardiography, and western blotting were used to evaluate the electrophysiological activity, cardiac structure, fatty acid metabolism, inflammation, and PPAR isoform expressions in the control and streptozotocin-nicotinamide-induced DM rats with or without MPT0E014. Compared to control, DM and MPT0E014-treated DM rats had elevated blood glucose levels and lower body weights. However, MPT0E014-treated DM and control rats had smaller left ventricular end-diastolic diameter and shorter QT interval than DM rats. The control and MPT0E014-treated DM rats had greater cardiac PPAR-α and PPAR-δ protein expressions, but less cardiac PPAR-γ than DM rats. Moreover, control and MPT0E014-treated DM rats had lower concentrations of 5′ adenosine monophosphate-activated protein kinase 2α, PPAR-γ coactivator 1α, phosphorylated acetyl CoA carboxylase, cluster of differentiation 36, diacylglycerol acyltransferase 1 (DGAT1, DGAT2, tumor necrosis factor-α, and interleukin-6 protein than DM rats. HDAC inhibition significantly attenuated DM cardiomyopathy through modulation of cardiac PPARS, fatty acid metabolism, and proinflammatory cytokines.

  14. Patch in Cardiac Surgery

    Directory of Open Access Journals (Sweden)

    Alireza Alizadeh Ghavidel

    2014-06-01

    Full Text Available Introduction: Excessive bleeding presents a risk for the patient in cardiovascular surgery. Local haemostatic agents are of great value to reduce bleeding and related complications. TachoSil (Nycomed, Linz, Austria is a sterile, haemostatic agent that consists of an equine collagen patchcoated with human fibrinogen and thrombin. This study evaluated the safety and efficacy of TachoSil compared to conventional technique.Methods: Forty-two patients scheduled for open heart surgeries, were entered to this study from August 2010 to May 2011. After primary haemostatic measures, patients divided in two groups based on surgeon’s judgment. Group A: 20 patients for whom TachoSil was applied and group B: 22 patients that conventional method using Surgicel (13 patients or wait and see method (9 cases, were performed in order to control the bleeding. In group A, 10 patients were male with mean age of 56.95±15.67 years and in group B, 9 cases were male with mean age of 49.95±14.41 years. In case group 70% (14/20 of the surgeries were redo surgeries versus 100% (22/22 in control group.Results: Baseline characteristics were similar in both groups. In TachoSil group 75% of patients required transfusion versus 90.90% in group B (P=0.03.Most transfusions consisted of packed red blood cell; 2±1.13 units in group A versus 3.11±1.44 in group B (P=0.01, however there were no significant differences between two groups regarding the mean total volume of intra and post-operative bleeding. Re-exploration was required in 10% in group A versus 13.63% in group B (P=0.67.Conclusion: TachoSil may act as a superior alternative in different types of cardiac surgery in order to control the bleeding and therefore reducing transfusion requirement.

  15. Cardiac output monitoring

    Directory of Open Access Journals (Sweden)

    Mathews Lailu

    2008-01-01

    Full Text Available Minimally invasive and non-invasive methods of estimation of cardiac output (CO were developed to overcome the limitations of invasive nature of pulmonary artery catheterization (PAC and direct Fick method used for the measurement of stroke volume (SV. The important minimally invasive techniques available are: oesophageal Doppler monitoring (ODM, the derivative Fick method (using partial carbon dioxide (CO 2 breathing, transpulmonary thermodilution, lithium indicator dilution, pulse contour and pulse power analysis. Impedance cardiography is probably the only non-invasive technique in true sense. It provides information about haemodynamic status without the risk, cost and skill associated with the other invasive or minimally invasive techniques. It is important to understand what is really being measured and what assumptions and calculations have been incorporated with respect to a monitoring device. Understanding the basic principles of the above techniques as well as their advantages and limitations may be useful. In addition, the clinical validation of new techniques is necessary to convince that these new tools provide reliable measurements. In this review the physics behind the working of ODM, partial CO 2 breathing, transpulmonary thermodilution and lithium dilution techniques are dealt with. The physical and the physiological aspects underlying the pulse contour and pulse power analyses, various pulse contour techniques, their development, advantages and limitations are also covered. The principle of thoracic bioimpedance along with computation of CO from changes in thoracic impedance is explained. The purpose of the review is to help us minimize the dogmatic nature of practice favouring one technique or the other.

  16. Characterization of respiratory and cardiac motion from electro-anatomical mapping data for improved fusion of MRI to left ventricular electrograms.

    Directory of Open Access Journals (Sweden)

    Sébastien Roujol

    Full Text Available Accurate fusion of late gadolinium enhancement magnetic resonance imaging (MRI and electro-anatomical voltage mapping (EAM is required to evaluate the potential of MRI to identify the substrate of ventricular tachycardia. However, both datasets are not acquired at the same cardiac phase and EAM data is corrupted with respiratory motion limiting the accuracy of current rigid fusion techniques. Knowledge of cardiac and respiratory motion during EAM is thus required to enhance the fusion process. In this study, we propose a novel approach to characterize both cardiac and respiratory motion from EAM data using the temporal evolution of the 3D catheter location recorded from clinical EAM systems. Cardiac and respiratory motion components are extracted from the recorded catheter location using multi-band filters. Filters are calibrated for each EAM point using estimates of heart rate and respiratory rate. The method was first evaluated in numerical simulations using 3D models of cardiac and respiratory motions of the heart generated from real time MRI data acquired in 5 healthy subjects. An accuracy of 0.6-0.7 mm was found for both cardiac and respiratory motion estimates in numerical simulations. Cardiac and respiratory motions were then characterized in 27 patients who underwent LV mapping for treatment of ventricular tachycardia. Mean maximum amplitude of cardiac and respiratory motion was 10.2±2.7 mm (min = 5.5, max = 16.9 and 8.8±2.3 mm (min = 4.3, max = 14.8, respectively. 3D Cardiac and respiratory motions could be estimated from the recorded catheter location and the method does not rely on additional imaging modality such as X-ray fluoroscopy and can be used in conventional electrophysiology laboratory setting.

  17. Anti-Ro/SSA antibodies and cardiac arrhythmias in the adult: facts and hypotheses.

    Science.gov (United States)

    Lazzerini, P E; Capecchi, P L; Laghi-Pasini, F

    2010-09-01

    It is well established that the passive trans-placental passage of anti-Ro/SSA antibodies from mother to foetus is associated with the risk to develop an uncommon syndrome named neonatal lupus (NLE), where the congenital heart block represents the most severe clinical feature. Recent evidence demonstrated that also adult heart, classically considered invulnerable to the anti-Ro/SSA antibodies, may represent a target of the arrhythmogenicity of these autoantibodies. In particular, the prolongation of the QTc interval appears the most frequent abnormality observed in adults with circulating anti-Ro/SSA antibodies, with some data suggesting an association with an increased risk of ventricular arrhythmias, also life threatening. Moreover, even though the association between anti-Ro/SSA antibodies and conduction disturbances is undoubtedly less evident in adults than in infants, from the accurate dissection of the literature data the possibility arises that sometimes also the adult cardiac conduction tissue may be affected by such antibodies. The exact arrhythmogenic mechanisms involved in foetus/newborns and adults, respectively, have not been completely clarified as yet. However, increasing evidence suggests that anti-Ro/SSA antibodies may trigger rhythm disturbances through an inhibiting cross-reaction with several cardiac ionic channels, particularly the calcium channels (L-type and T-type), but also the potassium channel hERG, whose different expression and involvement in the cardiac electrophysiology during lifespan might account for the occurrence of age-related differences.

  18. Recurrent cardiac events in patients with idiopathic ventricular fibrillation, excluding patients with the Brugada syndrome

    Directory of Open Access Journals (Sweden)

    Philippon François

    2005-01-01

    Full Text Available Abstract Background The recurrence of cardiac events in patients with idiopathic ventricular fibrillation (VF excluding patients with the Brugada syndrome is unclear since this entity remains present in previous studies. Methods Since 1992, 18 patients (72% male with idiopathic VF out of 455 ICD implants were treated with an implantable cardioverter defibrillator (ICD. The mean age at first ICD implantation was 42 ± 14 years. Brugada syndrome, as well as other primary electrical diseases (e.g. long QT, were systematically excluded in all patients by the absence of the typical electrocardiogram (ST elevation in the right precordial leads at rest and/or after pharmacological tests (ajmaline, flecainide, or procainamide. Recurrence of cardiac events was prospectively assessed. Results During a mean follow-up period of 41 ± 27 months, VF recurrence with appropriate shock occurred in 7 patients (39% covering a total of 27 shocks. The median time to first appropriate shock was 12 ± 9 months. There were no deaths. In the electrophysiological study, 39% of patients were inducible, but inducibility failed to predict subsequent arrhythmic events. Forty-four percent of patients suffered 21 inappropriate shocks, which were caused by sinus tachycardia, atrial arrhythmias or lead malfunction. Conclusion Idiopathic ventricular fibrillation patients have a high recurrence rate of potentially fatal ventricular arrhythmias, excluding patients with the Brugada syndrome or other known causes. ICD prevents sudden cardiac death but inappropriate shocks remained a major issue in this young and active population.

  19. Cardiac microstructure: implications for electrical propagation and defibrillation in the heart.

    Science.gov (United States)

    Hooks, Darren A; Tomlinson, Karl A; Marsden, Scott G; LeGrice, Ian J; Smaill, Bruce H; Pullan, Andrew J; Hunter, Peter J

    2002-08-23

    Our understanding of the electrophysiological properties of the heart is incomplete. We have investigated two issues that are fundamental to advancing that understanding. First, there has been widespread debate over the mechanisms by which an externally applied shock can influence a sufficient volume of heart tissue to terminate cardiac fibrillation. Second, it has been uncertain whether cardiac tissue should be viewed as an electrically orthotropic structure, or whether its electrical properties are, in fact, isotropic in the plane orthogonal to myofiber direction. In the present study, a computer model that incorporates a detailed three-dimensional representation of cardiac muscular architecture is used to investigate these issues. We describe a bidomain model of electrical propagation solved in a discontinuous domain that accurately represents the microstructure of a transmural block of rat left ventricle. From analysis of the model results, we conclude that (1) the laminar organization of myocytes determines unique electrical properties in three microstructurally defined directions at any point in the ventricular wall of the heart, and (2) interlaminar clefts between layers of cardiomyocytes provide a substrate for bulk activation of the ventricles during defibrillation.

  20. Computed tomography of cardiac pseudotumors and neoplasms.

    Science.gov (United States)

    Anavekar, Nandan S; Bonnichsen, Crystal R; Foley, Thomas A; Morris, Michael F; Martinez, Matthew W; Williamson, Eric E; Glockner, James F; Miller, Dylan V; Breen, Jerome F; Araoz, Philip A

    2010-07-01

    Important features of cardiac masses can be clearly delineated on cardiac computed tomography (CT) imaging. This modality is useful in identifying the presence of a mass, its relationship with cardiac and extracardiac structures, and the features that distinguish one type of mass from another. A multimodality approach to the evaluation of cardiac tumors is advocated, with the use of echocardiography, CT imaging and magnetic resonance imaging as appropriately indicated. In this article, various cardiac masses are described, including pseudotumors and true cardiac neoplasms, and the CT imaging findings that may be useful in distinguishing these rare entities are presented. PMID:20705174

  1. Effects of hypertonic sodium chloride solution on the electrophysiologic alterations caused by bupivacaine in the dog heart

    Directory of Open Access Journals (Sweden)

    Scalabrini A.

    2003-01-01

    Full Text Available The effects of various hypertonic solutions on the intraventricular conduction, ventricular repolarization and the arrhythmias caused by the intravenous (iv injection of bupivacaine (6.5 mg/kg were studied in sodium pentobarbital-anesthetized mongrel dogs. Hypertonic solutions, given iv 5 min before bupivacaine, were 7.5% (w/v NaCl, 5.4% (w/v LiCl, 50% (w/v glucose (2,400 mOsm/l, 5 ml/kg, or 20% (w/v mannitol (1,200 mOsm/l, 10 ml/kg. Bupivacaine induced severe arrhythmias and ventricular conduction and repolarization disturbances, as reflected by significant increases in QRS complex duration, HV interval, IV interval and monophasic action potential duration, as well as severe hemodynamic impairment. Significant prevention against ventricular electrophysiologic and hemodynamic disturbances and ventricular arrhythmias was observed with 7.5% NaCl (percent increase in QRS complex duration: 164.4 ± 21.8% in the non-pretreated group vs 74.7 ± 14.1% in the pretreated group, P<0.05; percent increase in HV interval: 131.4 ± 16.1% in the non-pretreated group vs 58.2 ± 7.5% in the pretreated group, P<0.05; percent increase in monophasic action potential duration: 22.7 ± 6.8% in the non-pretreated group vs 9.8 ± 6.3% in the pretreated group, P<0.05; percent decrease in cardiac index: -46 ± 6% in the non-pretreated group vs -28 ± 5% in the pretreated group, P<0.05. The other three hypertonic solutions were ineffective. These findings suggest an involvement of sodium ions in the mechanism of hypertonic protection.

  2. Existence of a sex pheromone in Triatoma infestans (Hemiptera: Reduvidae: II. Electrophysiological correlates

    Directory of Open Access Journals (Sweden)

    Maria G. de Brito Sanchez

    1995-10-01

    Full Text Available The stimulus provided by a copulating pair of Triatoma infestans significantly affects the electrical activity of the nervous system of Triatoma infestans. Electrophysiological recordings were perfomed on stationary adult males presented with stimuli of an air current carrying odors from males, females, non-copulating pairs and mating pairs. The electrophysiological response was characterized by the low frequency occurrence of biphasic compound impulses. A significant increase in the frequency of the impulses occurred in stationary males when exposed to air currents of mating pairs, when compared to that evoked by a clean air stream. Analysis of the time course of the assays, showed that the electrophisiological activity during the copula was higher than prior to or after copula. The electrophysiological evidence presented here strongly supports the existence of pheromone(s released by one or both sexes during mating and which is perceived by male chemoreceptors located on the antennae.

  3. Electrophysiological, transcriptomic and morphologic profiling of single neurons using Patch-seq.

    Science.gov (United States)

    Cadwell, Cathryn R; Palasantza, Athanasia; Jiang, Xiaolong; Berens, Philipp; Deng, Qiaolin; Yilmaz, Marlene; Reimer, Jacob; Shen, Shan; Bethge, Matthias; Tolias, Kimberley F; Sandberg, Rickard; Tolias, Andreas S

    2016-02-01

    Despite the importance of the mammalian neocortex for complex cognitive processes, we still lack a comprehensive description of its cellular components. To improve the classification of neuronal cell types and the functional characterization of single neurons, we present Patch-seq, a method that combines whole-cell electrophysiological patch-clamp recordings, single-cell RNA-sequencing and morphological characterization. Following electrophysiological characterization, cell contents are aspirated through the patch-clamp pipette and prepared for RNA-sequencing. Using this approach, we generate electrophysiological and molecular profiles of 58 neocortical cells and show that gene expression patterns can be used to infer the morphological and physiological properties such as axonal arborization and action potential amplitude of individual neurons. Our results shed light on the molecular underpinnings of neuronal diversity and suggest that Patch-seq can facilitate the classification of cell types in the nervous system. PMID:26689543

  4. Distinct electrophysiological potentials for intention in action and prior intention for action

    DEFF Research Database (Denmark)

    Vinding, Mikkel C; Jensen, Mads; Overgaard, Morten

    2014-01-01

    The role of conscious intention in relation to motoric movements has become a major topic of investigation in neuroscience. Traditionally, reports of conscious intention have been compared to various features of the readiness-potential (RP) – an electrophysiological signal that appears before...... voluntary movements. Experiments, however, tend to study intentions in immediate relation to movements (proximal intentions), thus ignoring other aspects of intentions such as planning or deciding in advance of movement (distal intentions). The current study examines the difference in electrophysiological...... activity between proximal intention and distal intention, using electroencephalography (EEG). Participants had to form an intention to move and then wait 2.5 sec before performing the actual movement. In this way, the electrophysiological activity related to forming a conscious intention was separated from...

  5. Cardiac Penetrating Injuries and Pseudoaneurysm

    Institute of Scientific and Technical Information of China (English)

    CHEN Shifeng

    2002-01-01

    Objective To discuss the early diagnosis and treatment of cardiac penetrating injuries and pseudoaneurysm. Methods 18 cases of cardiac penetrating injuries, in which 2 cases were complicated with pseudoaneurysm, were diagnosed by emergency operation and color Doppler echocardiography between May 1973 and Dec. 2001 in our hospital. The basis for emergency operation is the injured path locating in cardiac dangerous zone, severe shock or pericardial tamponade. ResultsAmong 18 cases of this study, 17 cases underwent emergency operation. During the operation, 11 cases were found injured in right ventricle, 2 cases were found injured in right atrium, 1 case was found injured in pulmonary artery,4 cases were found injured in left ventricle, 2 cases were found complicated with pseudoaneurysm. 17cases underwent cardiac repair including 1 case of rupture of aneurysm. 1 case underwent elective aneurysm resection. In whole group, 15 cases survived(83.33% ), 3 cases died( 16.67%). The cause of death is mainly hemorrhagic shock. Conclusion Highly suspicious cardiac penetrating injuries or hemopericaridium should undergo direct operative exploration. Pseudoaneurysm should be resected early,which can prevent severe complications.

  6. Vitamin D and Cardiac Differentiation.

    Science.gov (United States)

    Kim, Irene M; Norris, Keith C; Artaza, Jorge N

    2016-01-01

    Calcitriol (1,25-dihydroxycholecalciferol or 1,25-D3) is the hormonally active metabolite of vitamin D. Experimental studies of vitamin D receptors and 1,25-D3 establish calcitriol to be a critical regulator of the structure and function of the heart. Clinical studies link vitamin D deficiency with cardiovascular disease (CVD). Emerging evidence demonstrates that calcitriol is highly involved in CVD-related signaling pathways, particularly the Wnt signaling pathway. Addition of 1,25-D3 to cardiomyocyte cells and examination of its effects on cardiomyocytes and mainly Wnt11 signaling allowed the specific characterization of the role of calcitriol in cardiac differentiation. 1,25-D3 is demonstrated to: (i) inhibit cell proliferation without promoting apoptosis; (ii) decrease expression of genes related to the regulation of the cell cycle; (iii) promote formation of cardiomyotubes; (iv) induce expression of casein kinase-1-α1, a negative regulator of the canonical Wnt signaling pathway; and (v) increase expression of noncanonical Wnt11, which has been recognized to induce cardiac differentiation during embryonic development and in adult cells. Thus, it appears that vitamin D promotes cardiac differentiation through negative modulation of the canonical Wnt signaling pathway and upregulation of noncanonical Wnt11 expression. Future work to elucidate the role(s) of vitamin D in cardiovascular disorders will hopefully lead to improvement and potentially prevention of CVD, including abnormal cardiac differentiation in settings such as postinfarction cardiac remodeling. PMID:26827957

  7. Cardiac factors in orthostatic hypotension

    Science.gov (United States)

    Löllgen, H.; Dirschedl, P.; Koppenhagen, K.; Klein, K. E.

    Cardiac function is determined by preload, afterload, heart rate and contractility. During orthostatic stress, the footward blood shift is compensated for by an increase of afterload. LBNP is widely used to analyze effects of volume displacement during orthostatic stress. Comparisons of invasive ( right heart catheterization) and non-invasive approach (echocardiography) yielded similar changes. Preload and afterload change with graded LBNP, heart rate increases, and stroke volume and cardiac output decrease. Thus, the working point on the left ventricular function curve is shifted to the left and downward, similar to hypovolemia. However, position on the Frank-Starling curve, the unchanged ejection fraction, and the constant Vcf indicate a normal contractile state during LBNP. A decrease of arterial oxygen partial pressure during LBNP shwos impaired ventilation/perfusion ratio. Finally, LBNP induced cardiac and hemodynamic changes can be effectively countermeasured by dihydroergotamine, a potent venoconstrictor. Comparison of floating catheter data with that of echocardiography resulted in close correlation for cardiac output and stroke volume. In addition, cardiac dimensions changed in a similar way during LBNP. From our findings, echocardiography as a non-invasive procedure can reliably used in LBNP and orthostatic stress tests. Some informations can be obtained on borderline values indicating collaps or orthostatic syncope. Early fainters can be differentiated from late fainters by stroke volume changes.

  8. Animal models of cardiac cachexia.

    Science.gov (United States)

    Molinari, Francesca; Malara, Natalia; Mollace, Vincenzo; Rosano, Giuseppe; Ferraro, Elisabetta

    2016-09-15

    Cachexia is the loss of body weight associated with several chronic diseases including chronic heart failure (CHF). The cachectic condition is mainly due to loss of skeletal muscle mass and adipose tissue depletion. The majority of experimental in vivo studies on cachexia rely on animal models of cancer cachexia while a reliable and appropriate model for cardiac cachexia has not yet been established. A critical issue in generating a cardiac cachexia model is that genetic modifications or pharmacological treatments impairing the heart functionality and used to obtain the heart failure model might likely impair the skeletal muscle, this also being a striated muscle and sharing with the myocardium several molecular and physiological mechanisms. On the other hand, often, the induction of heart damage in the several existing models of heart failure does not necessarily lead to skeletal muscle loss and cachexia. Here we describe the main features of cardiac cachexia and illustrate some animal models proposed for cardiac cachexia studies; they include the genetic calsequestrin and Dahl salt-sensitive models, the monocrotaline model and the surgical models obtained by left anterior descending (LAD) ligation, transverse aortic constriction (TAC) and ascending aortic banding. The availability of a specific animal model for cardiac cachexia is a crucial issue since, besides the common aspects of cachexia in the different syndromes, each disease has some peculiarities in its etiology and pathophysiology leading to cachexia. Such peculiarities need to be unraveled in order to find new targets for effective therapies. PMID:27317993

  9. Epicardial Lineages and Cardiac Repair

    Directory of Open Access Journals (Sweden)

    Manvendra K. Singh

    2013-08-01

    Full Text Available The death of cardiac myocytes resulting from myocardial infarction is a major cause of heart failure worldwide. Effective therapies for regenerating lost cardiac myocytes are lacking. Recently, the epicardium has been implicated as a source of inflammatory cytokines, growth factors and progenitor cells that modulate the response to myocardial injury. During embryonic development, epicardially-derived cells have the potential to differentiate into multiple cardiac lineages, including fibroblasts, vascular smooth muscle and potentially other cell types. In the healthy adult heart, epicardial cells are thought to be generally quiescent. However, injury of the adult heart results in reactivation of a developmental gene program in the epicardium, which leads to increased epicardial cell proliferation and differentiation of epicardium-derived cells (EPDCs into various cardiac lineages. Recent work suggests that epicardial reactivation after injury is accompanied by, and contributes to, a robust inflammatory response. In this review, we describe the current status of research related to epicardial biology in cardiac development and regeneration, highlighting important recent discoveries and ongoing controversies.

  10. Excitation model of pacemaker cardiomyocytes of cardiac conduction system

    Science.gov (United States)

    Grigoriev, M.; Babich, L.

    2015-11-01

    Myocardium includes typical and atypical cardiomyocytes - pacemakers, which form the cardiac conduction system. Excitation from the atrioventricular node in normal conditions is possible only in one direction. Retrograde direction of pulses is impossible. The most important prerequisite for the work of cardiomyocytes is the anatomical integrity of the conduction system. Changes in contractile force of the cardiomyocytes, which appear periodically, are due to two mechanisms of self-regulation - heterometric and homeometric. Graphic course of the excitation pulse propagation along the heart muscle more accurately reveals the understanding of the arrhythmia mechanism. These models have the ability to visualize the essence of excitation dynamics. However, they do not have the proper forecasting function for result estimation. Integrative mathematical model enables further investigation of general laws of the myocardium active behavior, allows for determination of the violation mechanism of electrical and contractile function of cardiomyocytes. Currently, there is no full understanding of the topography of pacemakers and ionic mechanisms. There is a need for the development of direction of mathematical modeling and comparative studies of the electrophysiological arrangement of cells of atrioventricular connection and ventricular conduction system.

  11. Cardiac ion channel modulation by the hypoglycaemic agent rosiglitazone.

    Science.gov (United States)

    Hancox, J C

    2011-06-01

    The hypoglycaemic thiazolidinedione rosiglitazone is used clinically in the treatment of type 2 diabetes. However, in 2010, information relating to rosiglitazone-associated increased cardiovascular risk led the European Medicines Agency to recommend suspension of marketing authorizations for rosiglitazone-containing anti-diabetes drugs, while the US Food and Drug Administration recommended significant restriction on the agent's use. Two timely studies in this issue of the British Journal of Phrarmacology provide new information regarding modification of cardiac cellular electrophysiology by rosiglitazone. Szentandrássy et al. demonstrate canine ventricular action potential modification and concentration-dependent suppression of L-type Ca current and of transient outward and rapid delayed rectifier K currents. Jeong et al. demonstrate concentration-dependent inhibition of recombinant K(v) 4.3 channels, providing mechanistic insight into the likely molecular basis of transient outward K current inhibition by the compound. Further studies using diabetic models would be of value to determine whether, in a diabetic setting, rosiglitazone modification of these channels could affect the risk of arrhythmia at clinically relevant drug concentrations. PMID:21561443

  12. Cardiac perioperative complications in noncardiac surgery

    Directory of Open Access Journals (Sweden)

    Radovanović Dragana

    2008-01-01

    Full Text Available Anesthesiologists are confronted with an increasing population of patients undergoing noncardiac surgery who are at risk for cardiac complications in the perioperative period. Perioperative cardiac complications are responsible for significant mortality and morbidity. The aim of the present study was to determine the incidence of perioperative (operative and postoperative cardiac complications and correlations between the incidence of perioperative cardiac complications and type of surgical procedure, age, presence of concurrent diseases. A total of 100 patients with cardiac diseases undergoing noncardiac surgery were included in the prospective study (Group A 50 patients undergoing intraperitoneal surgery and Group B 50 patients undergoing breast and thyroid surgery. The patients were followed up during the perioperative period and after surgery until leaving hospital to assess the occurrence of cardiac events. Cardiac complications (systemic arterial hypertension, systemic arterial hypotension, abnormalities of cardiac conduction and cardiac rhythm, perioperative myocardial ischemia and acute myocardial infarction occurred in 64% of the patients. One of the 100 patients (1% had postoperative myocardial infarction which was fatal. Systemic arterial hypertension occurred in 57% of patients intraoperatively and 33% postoperatively, abnormalities of cardiac rhythm in 31% of patients intraoperatively and 17% postoperatively, perioperative myocardial ischemia in 23% of patients intraoperatively and 11% of postoperatively. The most often cardiac complications were systemic arterial hypertension, abnormalities of cardiac rhythm and perioperative myocardial ischemia. Factors independently associated with the incidence of cardiac complications included the type of surgical procedure, advanced age, duration of anaesthesia and surgery, abnormal preoperative electrocardiogram, abnormal preoperative chest radiography and diabetes.

  13. Integration of Optical Manipulation and Electrophysiological Tools to Modulate and Record Activity in Neural Networks

    Science.gov (United States)

    Difato, F.; Schibalsky, L.; Benfenati, F.; Blau, A.

    2011-07-01

    We present an optical system that combines IR (1064 nm) holographic optical tweezers with a sub-nanosecond-pulsed UV (355 nm) laser microdissector for the optical manipulation of single neurons and entire networks both on transparent and non-transparent substrates in vitro. The phase-modulated laser beam can illuminate the sample concurrently or independently from above or below assuring compatibility with different types of microelectrode array and patch-clamp electrophysiology. By combining electrophysiological and optical tools, neural activity in response to localized stimuli or injury can be studied and quantified at sub-cellular, cellular, and network level.

  14. The acute effects of intravenously administered mibefradil, a new calcium antagonist, on the electrophysiologic characteristics of the human heart

    NARCIS (Netherlands)

    Rosenquist, M; BrembillaPerrot, B; Meinertz, T; Neugebauer, A; Crijns, HJMG; Smeets, JLRM; vanderVring, JAFM; Fromer, M; Kobrin, [No Value

    1997-01-01

    Objective: This multicenter, double-blind, placebo-controlled, parallel-group study was designed to assess the acute effects of intravenous mibefradil on the electrophysiologic characteristics of the human heart. Methods: Seventy-one patients referred for routine electrophysiologic testing were rand

  15. Complications after cardiac implantable electronic device implantations

    DEFF Research Database (Denmark)

    Kirkfeldt, Rikke Esberg; Johansen, Jens Brock; Nohr, Ellen Aagaard;

    2013-01-01

    Complications after cardiac implantable electronic device (CIED) treatment, including permanent pacemakers (PMs), cardiac resynchronization therapy devices with defibrillators (CRT-Ds) or without (CRT-Ps), and implantable cardioverter defibrillators (ICDs), are associated with increased patient...

  16. Sudden Cardiac Arrest (SCA) Risk Assessment

    Science.gov (United States)

    ... Find a Specialist Share Twitter Facebook SCA Risk Assessment Sudden Cardiac Arrest (SCA) occurs abruptly and without ... of all ages and health conditions. Start Risk Assessment The Sudden Cardiac Arrest (SCA) Risk Assessment Tool ...

  17. An update on insertable cardiac monitors

    DEFF Research Database (Denmark)

    Olsen, Flemming J; Biering-Sørensen, Tor; Krieger, Derk W

    2015-01-01

    Continuous cardiac rhythm monitoring has undergone compelling progress over the past decades. Cardiac monitoring has emerged from 12-lead electrocardiograms being performed at the discretion of the treating physician to in-hospital telemetry, Holter monitoring, prolonged external event monitoring...

  18. Electroactive polyurethane/siloxane derived from castor oil as a versatile cardiac patch, part II: HL-1 cytocompatibility and electrical characterizations.

    Science.gov (United States)

    Baheiraei, Nafiseh; Gharibi, Reza; Yeganeh, Hamid; Miragoli, Michele; Salvarani, Nicolò; Di Pasquale, Elisa; Condorelli, Gianluigi

    2016-06-01

    In first part of this experiment, biocompatibility of the newly developed electroactive polyurethane/siloxane films containing aniline tetramer moieties was demonstrated with proliferation and differentiation of C2C12 myoblasts. Here we further assessed the cytocompatibility of the prepared samples with HL1-cell line, the electrophysiological properties and the patch clamp recording of the seeded cells over the selected electroactive sample. Presence of electroactive aniline tetramer in the structure of polyurethane/siloxane led to the increased expression of cardiac-specific genes of HL-1 cells involved in muscle contraction and electrical coupling. Our results showed that expression of Cx43, TrpT-2, and SERCA genes was significantly increased in conductive sample compared to tissue culture plate and the corresponding non-conductive analogous. The prepared materials were not only biocompatible in terms of cellular toxicity, but did not alter the intrinsic electrical characteristics of HL-1 cells. Embedding the electroactive moiety into the prepared films improved the properties of these polymeric cardiac construct through the enhanced transmission of electrical signals between the cells. Based on morphological observation, calcium imaging and electrophysiological recordings, we demonstrated the potential applicability of these materials for cardiac tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1398-1407, 2016. PMID:26822463

  19. Elevated sensitivity to cardiac ischemia in proteinuric rats is independent of adverse cardiac remodeling

    NARCIS (Netherlands)

    Szymanski, Mariusz K.; Hillege, Hans L.; Danser, A. H. Jan; Garrelds, Ingrid M.; Schoemaker, Regien G.

    2013-01-01

    Objectives: Chronic renal dysfunction severely increases cardiovascular risk. Adverse cardiac remodeling is suggested to play a major role as predisposition for increased cardiac ischemic vulnerability. The aim of the present study was to examine the role of adverse cardiac remodeling in cardiac sen

  20. Electrophysiology of Intuition: Pre-stimulus Responses in Group and Individual Participants Using a Roulette Paradigm.

    Science.gov (United States)

    McCraty, Rollin; Atkinson, Mike

    2014-03-01

    This study used electrophysiological measures of pre-stimulus effects that can occur prior to an unknown future event as an indicator of nonlocal intuition. Intuition in this context is considered as a process by which information normally outside the range of conscious awareness is detected at the cellular level by the heart, the brain, and the autonomic nervous system. This study extends the findings of previous experiments demonstrating that aspects of our physiology can respond to an emotionally engaging stimulus before it is actually experienced. The study evaluated a revised version of a roulette protocol, which included two pre-stimulus segments and included an analysis of the individual participant's data over eight separate trials in addition to a group-level analysis. We also assessed the potential effects of the moon phase on the pre-stimulus response outcomes and participant winning and amount won ratios. Data were collected under controlled laboratory conditions from 13 participants in 8 separate sessions using a modified version of a gambling paradigm protocol based on roulette. Half of the experimental sessions were conducted during the full moon phase and half during the new moon phase. Within each trial a total of three segments of physiological data were assessed. There were two separate pre-stimulus periods, pre-bet (4 sec) and postbet (12 sec), and a post-result period (6 sec). Participants were told that they were participating in a gambling experiment and were given an initial starting kitty and told they could keep any winnings over the course of 26 trials for each of the eight sessions. The physiological measures included the electrocardiogram (ECG), from which cardiac inter-beat-intervals (heart rate variability, HRV) were derived, and skin conductance. Before the participants participated in the first session, they completed the Cognitive Styles Index questionnaire, which assesses analytical vs intuitive styles. Overall, the results

  1. Electrophysiological Data and the Biophysical Modelling of Local Cortical Circuits

    Directory of Open Access Journals (Sweden)

    Dimitris Pinotsis

    2014-03-01

    neuroscience, see e.g. [2] for a review. In summary, neural fields include horizontal intrinsic connections within layers or laminae of the cortical sheet and prescribe the time evolution of cell activity – such as mean depolarization or (average action potential density. These models characterize current fluxes as continuous processes on the cortical sheet, using partial differential equations (PDEs. The key advance that neural field models offer, over other population models (like neural masses, is that they embody spatial parameters (like the density and extent of lateral connections. This allows one to model responses not just in time but also over space. Conversely, these models are particularly useful for explaining observed cortical responses over different spatial scales; for example, with high-density recordings, at the epidural or intracortical level. However, the impact of spatially extensive dynamics is not restricted to expression over space but can also have profound effects on temporal (e.g., spectral responses at one point (or averaged locally over the cortical surface. This means that neural field models may also play a key role in the modelling of non-invasive electrophysiological data that does not resolve spatial activity directly. Our overview comprises two parts: in the first part, we use neural fields to simulate neural activity and distinguish the effects of post synaptic filtering on predicted responses in terms of synaptic rate constants that correspond to different timescales and distinct neurotransmitters. This application of neural fields follows the tradition of many studies, in which neural fields (and mean field models in general have been used to explain cortical activity based on qualitative changes of models activity induced by changes in model parameters, like synaptic efficacy and connection strengths, see e.g.[3–8] . We will focus on the links between neuronal oscillations – mediated by the lateral propagation of neuronal spiking

  2. Cardiac regeneration by pharmacologically active microcarriers releasing growth factors and/or transporting adipose-derived stem cells

    Directory of Open Access Journals (Sweden)

    Monia Savi

    2014-01-01

    Full Text Available We tested the hypothesis that cardiac regeneration through local delivery of adipose-derived stem cells (ASCs, activation of resident cardiac stem cells via growth factors (GFs [hepatocyte growth factor (HGF and insulin-like growth factor 1 (IGF-1:GFs] or both, are improved by pharmacologically active microcarriers (PAMs interacting with cells/molecules conveyed on their surface. Rats with one-month old myocardial infarction were treated with ASCs, ASCs+PAMs, GF-releasing PAMs, ASCs+GF-releasing PAMs or vehicle. Two weeks later, hemodynamic function and inducibility of ventricular arrhythmias (VAs were assessed. Eventually, the hearts were subjected to anatomical and immunohistochemical analyses. A significant ASCs engraftment and the largest improvement in cardiac mechanics occurred in ASC+GF-releasing PAM rats which by contrast were more vulnerable to VAs. Thus, PAMs may improve cell/GF-based cardiac regeneration although caution should be paid on the electrophysiological impact of their physical interaction with the myocardium.

  3. [Cardiac output monitoring by impedance cardiography in cardiac surgery].

    Science.gov (United States)

    Shimizu, H; Seki, S; Mizuguchi, A; Tsuchida, H; Watanabe, H; Namiki, A

    1990-04-01

    The cardiac output monitoring by impedance cardiography, NCCOM3, was evaluated in adult patients (n = 12) who were subjected to coronary artery bypass grafting. Values of cardiac output measured by impedance cardiography were compared to those by the thermodilution method. Changes of base impedance level used as an index of thoracic fluid volume were also investigated before and after cardiopulmonary bypass (CPB). Correlation coefficient (r) of the values obtained by thermodilution with impedance cardiography was 0.79 and the mean difference was 1.29 +/- 16.9 (SD)% during induction of anesthesia. During the operation, r was 0.83 and the mean difference was -14.6 +/- 18.7%. The measurement by impedance cardiography could be carried out through the operation except when electro-cautery was used. Base impedance level before CPB was significantly lower as compared with that after CPB. There was a negative correlation between the base impedance level and central venous pressure (CVP). No patients showed any signs suggesting lung edema and all the values of CVP, pulmonary artery pressure and blood gas analysis were within normal ranges. From the result of this study, it was concluded that cardiac output monitoring by impedance cardiography was useful in cardiac surgery, but further detailed examinations will be necessary on the relationship between the numerical values of base impedance and the clinical state of the patients. PMID:2362347

  4. Health Literacy Predicts Cardiac Knowledge Gains in Cardiac Rehabilitation Participants

    Science.gov (United States)

    Mattson, Colleen C.; Rawson, Katherine; Hughes, Joel W.; Waechter, Donna; Rosneck, James

    2015-01-01

    Objective: Health literacy is increasingly recognised as a potentially important patient characteristic related to patient education efforts. We evaluated whether health literacy would predict gains in knowledge after completion of patient education in cardiac rehabilitation. Method: This was a re-post observational analysis study design based on…

  5. Regulation of Cardiac Hypertrophy: the nuclear option

    OpenAIRE

    Kuster, Diederik

    2011-01-01

    textabstractCardiac hypertrophy is the response of the heart to an increased workload. After myocardial infarction (MI) the surviving muscle tissue has to work harder to maintain cardiac output. This sustained increase in workload leads to cardiac hypertrophy. Despite its apparent appropriateness, cardiac hypertrophy is an independent risk factor for the development of heart failure and is therefore called pathological hypertrophy. That hypertrophy is not bad per se, is illustrated by the hyp...

  6. Selection and collection of multi parameter physiological data for cardiac rhythm diagnostic algorithm development

    Science.gov (United States)

    Bostock, J.; Weller, P.; Cooklin, M.

    2010-07-01

    Automated diagnostic algorithms are used in implantable cardioverter-defibrillators (ICD's) to detect abnormal heart rhythms. Algorithms misdiagnose and improved specificity is needed to prevent inappropriate therapy. Knowledge engineering (KE) and artificial intelligence (AI) could improve this. A pilot study of KE was performed with artificial neural network (ANN) as AI system. A case note review analysed arrhythmic events stored in patients ICD memory. 13.2% patients received inappropriate therapy. The best ICD algorithm had sensitivity 1.00, specificity 0.69 (pcollected from 65 patients during cardiac electrophysiological studies. 5 incomplete datasets were due to technical failures. We concluded that KE successfully guided selection of parameters and ANN produced a usable system and that complex data collection carries greater risk of technical failure, leading to data loss.

  7. Multichannel SQUID system detecting tangential components of the cardiac magnetic field

    Science.gov (United States)

    Tsukada, Keiji; Haruta, Yasuhiro; Adachi, Akira; Ogata, Hisanao; Komuro, Takanori; Ito, Tsuyoshi; Takada, Youichi; Kandori, Akihiko; Noda, Yasunaga; Terada, Yasushi; Mitsui, Toshio

    1995-10-01

    The 32-channel SQUID system described here is used for diagnosing heart disease by measuring the x and y components of the cardiac magnetic field. To detect a magnetic field parallel to the body surface, it uses a compact hybrid superconducting quantum interference device (SQUID) gradiometer consisting of a planar pickup coil (fabricated using thin-film techniques) and a square double-washer dc-SQUID having large voltage-flux transfer function. The SQUIDs are operated in a flux-locked mode using simple readout circuits connected directly to the preamplifier without additional positive feedback. The system is installed in a magnetically shielded room in a hospital. A low noise characteristics lower than 10 ft/√ Hz in a white noise is obtained in the hospital. Examples of tangential magnetocardiogram (MCG) measurements presented here show that the MCG obtained using this gradiometer makes it easy to visually estimate the electrophysiological behavior of the heart.

  8. Functional coupling with cardiac muscle promotes maturation of hPSC-derived sympathetic neurons

    Science.gov (United States)

    Oh, Yohan; Cho, Gun-Sik; Li, Zhe; Hong, Ingie; Zhu, Renjun; Kim, Min-Jeong; Kim, Yong Jun; Tampakakis, Emmanouil; Tung, Leslie; Huganir, Richard; Dong, Xinzhong; Kwon, Chulan; Lee, Gabsang

    2016-01-01

    Summary Neurons derived from human pluripotent stem cells (hPSCs) are powerful tools for studying human neural development and diseases. Robust functional coupling of hPSC-derived neurons with target tissues in vitro is essential for modeling intercellular physiology in a dish and to further translational studies, but has proven difficult to achieve. Here, we derive sympathetic neurons from hPSCs and show they can form physical and functional connections with cardiac muscle cells. Using multiple hPSC reporter lines, we recapitulated human autonomic neuron development in vitro and successfully isolated PHOX2B:eGFP+ neurons that exhibit sympathetic marker expression and electrophysiological properties, and norepinephrine secretion. Upon pharmacologic and optogenetic manipulation, PHOX:eGFP+ neurons controlled beating rates of cardiomyocytes, and the physical interactions between these cells increased neuronal maturation. This study provides a foundation for human sympathetic neuron specification and for hPSC-based neuronal control of organs in a dish. PMID:27320040

  9. Ensembles of engineered cardiac tissues for physiological and pharmacological study: heart on a chip.

    Science.gov (United States)

    Grosberg, Anna; Alford, Patrick W; McCain, Megan L; Parker, Kevin Kit

    2011-12-21

    Traditionally, muscle physiology experiments require multiple tissue samples to obtain morphometric, electrophysiological, and contractility data. Furthermore, these experiments are commonly completed one at a time on cover slips of single cells, isotropic monolayers, or in isolated muscle strips. In all of these cases, variability of the samples hinders quantitative comparisons among experimental groups. Here, we report the design of a "heart on a chip" that exploits muscular thin film technology--biohybrid constructs of an engineered, anisotropic ventricular myocardium on an elastomeric thin film--to measure contractility, combined with a quantification of action potential propagation, and cytoskeletal architecture in multiple tissues in the same experiment. We report techniques for real-time data collection and analysis during pharmacological intervention. The chip is an efficient means of measuring structure-function relationships in constructs that replicate the hierarchical tissue architectures of laminar cardiac muscle.

  10. MRI of cardiac rhabdomyoma in the fetus

    Energy Technology Data Exchange (ETDEWEB)

    Kivelitz, Dietmar E.; Muehler, Matthias [Institut fuer Radiologie, Medizinische Fakultaet, Humboldt-Universitaet zu Berlin, Charite, Schumannstrasse 20/21, 10098, Berlin (Germany); Rake, Annett; Chaoui, Rabih [Klinik fuer Gynaekologie und Geburtshilfe, Medizinische Fakultaet, Humboldt-Universitaet zu Berlin, Charite, Schumannstrasse 20/21, 10098, Berlin (Germany); Scheer, Ianina [Klinik fuer Strahlenheilkunde, Abteilung Paediatrische Radiologie, Medizinische Fakultaet, Humboldt-Universitaet zu Berlin, Charite, Schumannstrasse 20/21, 10098, Berlin (Germany)

    2004-08-01

    Primary cardiac tumors are rarely diagnosed in utero and are usually seen on prenatal echocardiography. Cardiac rhabdomyomata can be associated with tuberous sclerosis. Prenatal MRI can be performed to assess associated malformations. This case report illustrates the ability of fetal MRI to image cardiac rhabdomyata and compares it with prenatal and postnatal echocardiography. (orig.)

  11. Regulation of Cardiac Hypertrophy: the nuclear option

    NARCIS (Netherlands)

    D.W.D. Kuster (Diederik)

    2011-01-01

    textabstractCardiac hypertrophy is the response of the heart to an increased workload. After myocardial infarction (MI) the surviving muscle tissue has to work harder to maintain cardiac output. This sustained increase in workload leads to cardiac hypertrophy. Despite its apparent appropriateness, c

  12. Childhood cancer survivors: cardiac disease & social outcomes

    NARCIS (Netherlands)

    E.A.M. Feijen

    2015-01-01

    The thesis is divided in two parts; Cardiac health problems and healthcare consumption & social outcomes in CCS. The general aims of part 1 creates optimal conditions for the evaluation of cardiac events in 5-year childhood cancer survivors, evaluation of the long term risk of cardiac events, and to

  13. Cardiac tumors: optimal cardiac MR sequences and spectrum of imaging appearances.

    LENUS (Irish Health Repository)

    O'Donnell, David H

    2012-02-01

    OBJECTIVE: This article reviews the optimal cardiac MRI sequences for and the spectrum of imaging appearances of cardiac tumors. CONCLUSION: Recent technologic advances in cardiac MRI have resulted in the rapid acquisition of images of the heart with high spatial and temporal resolution and excellent myocardial tissue characterization. Cardiac MRI provides optimal assessment of the location, functional characteristics, and soft-tissue features of cardiac tumors, allowing accurate differentiation of benign and malignant lesions.

  14. Cardiac connexins and impulse propagation

    NARCIS (Netherlands)

    J.A. Jansen; T.A.B. van Veen; J.M.T. de Bakker; H.V.M. van Rijen

    2010-01-01

    Gap junctions form the intercellular pathway for cell-to-cell transmission of the cardiac impulse from its site of origin, the sinoatrial node, along the atria, the atrioventricular conduction system to the ventricular myocardium. The component parts of gap junctions are proteins called connexins (C

  15. Cardiac abnormalities after subarachnoid hemorrhage

    NARCIS (Netherlands)

    Bilt, I.A.C. van der

    2016-01-01

    Aneurysmal subarachnoid hemorrhage(aSAH) is a devastating neurological disease. During the course of the aSAH several neurological and medical complications may occur. Cardiac abnormalities after aSAH are observed often and resemble stress cardiomyopathy or Tako-tsubo cardiomyopathy(Broken Heart Syn

  16. Molecular therapies for cardiac arrhythmias

    NARCIS (Netherlands)

    G.J.J. Boink

    2013-01-01

    Despite the ongoing advances in pharmacology, devices and surgical approaches to treat heart rhythm disturbances, arrhythmias are still a significant cause of death and morbidity. With the introduction of gene and cell therapy, new avenues have arrived for the local modulation of cardiac disease. Th

  17. Historical highlights in cardiac pacing.

    Science.gov (United States)

    Geddes, L A

    1990-01-01

    The benchmarks in cardiac pacing are identified, beginning with F. Steiner (1871), who rhythmically stimulated the chloroform-arrested hearts of 3 horses, 1 donkey, 10 dogs, 14 cats, and 8 rabbits. The chloroform-arrested heart in human subjects was paced by T. Greene in the following year (1872) in the UK. In 1882, H. Ziemssen in Germany applied cardiac pacing to a 42-year old woman who had a large defect in the anterior left chest wall subsequent to resection of an enchondroma. Intentional cardiac pacing did not occur until 1932, when A.A. Hyman in the US demonstrated that cardiac pacing could be clinically practical. Hyman made a batteryless pacemaker for delivery in induction shock stimuli (60-120/min) to the atria. His pacemaker was powered by a hand-wound, spring-driven generator which provided 6 min of pacemaking without rewinding. Closed-chest ventricular pacing was introduced in the US in 1952 by P.M. Zoll et al. Zoll (1956) also introduced closed-chest ventricular defibrillation. W.L. Weirich et al. (1958) demonstrated that direct-heart stimulation in closed-chest patients could be achieved with slender wire electrodes. S. Furman and J.B. Schwedel (1959) developed a monopolar catheter electrode for ventricular pacing in man. In the same year, W. Greatbatch and W.M. Chardack developed the implantable pacemaker. PMID:18238328

  18. Cardiac resynchronization therapy in China

    Institute of Scientific and Technical Information of China (English)

    Wei HUA

    2006-01-01

    @@ Congestive heart failure (HF) is a major and growing public health problem. The therapeutic approach includes non-pharmacological measures, pharmacological therapy,mechanical devices, and surgery. Despite the benefits of optimal pharmacologic therapy, the prognosis is still not ideal. At this time, cardiac resynchronization therapy (CRT)has gained wide acceptance as an alternative treatment for HF patients with conduction delay.1

  19. Cardiac pacemakers and nuclear batteries

    International Nuclear Information System (INIS)

    Following the introduction giving the indications for cardiac pacemaker therapy with special regard to the use of pacemakers powered by nuclear batteries, reference is made to the resulting radiation exposure of the patient. The activities of the Federal Health Office in this field such as recommendations and surveys including the entire Federal Republic are outlined. (orig.)

  20. CARDIAC TRANSPLANTATION: AN ANESTHETIC CHALLENGE

    OpenAIRE

    Premalatha; Jayaraman,

    2014-01-01

    : Heart transplantation has emerged as the definitive therapy for patients with end-stage cardiomyopathy. The two most common forms of cardiac disease that lead to transplantation are ischemic cardiomyopathy and dilated cardiomyopathy, which together comprise approximately 90% of cases. The other less common forms of heart disease include viral cardiomyopathy, infiltrative cardiomyopathy, postpartum cardiomyopathy, valvular heart disease and congenital heart disease

  1. Epidural analgesia for cardiac surgery

    NARCIS (Netherlands)

    V. Svircevic; M.M. Passier; A.P. Nierich; D. van Dijk; C.J. Kalkman; G.J. van der Heijden

    2013-01-01

    Background A combination of general anaesthesia (GA) with thoracic epidural analgesia (TEA) may have a beneficial effect on clinical outcomes by reducing the risk of perioperative complications after cardiac surgery. Objectives The objective of this review was to determine the impact of perioperativ

  2. Combining non-invasive transcranial brain stimulation with neuroimaging and electrophysiology: Current approaches and future perspectives.

    Science.gov (United States)

    Bergmann, Til Ole; Karabanov, Anke; Hartwigsen, Gesa; Thielscher, Axel; Siebner, Hartwig Roman

    2016-10-15

    Non-invasive transcranial brain stimulation (NTBS) techniques such as transcranial magnetic stimulation (TMS) and transcranial current stimulation (TCS) are important tools in human systems and cognitive neuroscience because they are able to reveal the relevance of certain brain structures or neuronal activity patterns for a given brain function. It is nowadays feasible to combine NTBS, either consecutively or concurrently, with a variety of neuroimaging and electrophysiological techniques. Here we discuss what kind of information can be gained from combined approaches, which often are technically demanding. We argue that the benefit from this combination is twofold. Firstly, neuroimaging and electrophysiology can inform subsequent NTBS, providing the required information to optimize where, when, and how to stimulate the brain. Information can be achieved both before and during the NTBS experiment, requiring consecutive and concurrent applications, respectively. Secondly, neuroimaging and electrophysiology can provide the readout for neural changes induced by NTBS. Again, using either concurrent or consecutive applications, both "online" NTBS effects immediately following the stimulation and "offline" NTBS effects outlasting plasticity-inducing NTBS protocols can be assessed. Finally, both strategies can be combined to close the loop between measuring and modulating brain activity by means of closed-loop brain state-dependent NTBS. In this paper, we will provide a conceptual framework, emphasizing principal strategies and highlighting promising future directions to exploit the benefits of combining NTBS with neuroimaging or electrophysiology. PMID:26883069

  3. Electrophysiological Evidence of Heterogeneity in Visual Statistical Learning in Young Children with ASD

    Science.gov (United States)

    Jeste, Shafali S.; Kirkham, Natasha; Senturk, Damla; Hasenstab, Kyle; Sugar, Catherine; Kupelian, Chloe; Baker, Elizabeth; Sanders, Andrew J.; Shimizu, Christina; Norona, Amanda; Paparella, Tanya; Freeman, Stephanny F. N.; Johnson, Scott P.

    2015-01-01

    Statistical learning is characterized by detection of regularities in one's environment without an awareness or intention to learn, and it may play a critical role in language and social behavior. Accordingly, in this study we investigated the electrophysiological correlates of visual statistical learning in young children with autism…

  4. Think Globally: Cross-Linguistic Variation in Electrophysiological Activity during Sentence Comprehension

    Science.gov (United States)

    Bornkessel-Schlesewsky, Ina; Kretzschmar, Franziska; Tune, Sarah; Wang, Luming; Genc, Safiye; Philipp, Markus; Roehm, Dietmar; Schlesewsky, Matthias

    2011-01-01

    This paper demonstrates systematic cross-linguistic differences in the electrophysiological correlates of conflicts between form and meaning ("semantic reversal anomalies"). These engender P600 effects in English and Dutch (e.g. [Kolk et al., 2003] and [Kuperberg et al., 2003]), but a biphasic N400--late positivity pattern in German (Schlesewsky…

  5. Electrophysiological characterization of olfactory cell types in the antennae and palps of the housefly

    NARCIS (Netherlands)

    Kelling, FJ; Biancaniello, G; den Otter, CJ

    2002-01-01

    A set of odours was presented to the housefly Musca domestica and the electrophysiological responses of single olfactory receptor cells in the antennae and palps were recorded. The olfactory cells in the antennae of the housefly showed a large variability of response profiles, but multidimensional c

  6. Positive Behavioral and Electrophysiological Changes following Neurofeedback Training in Children with Autism

    Science.gov (United States)

    Pineda, J. A.; Brang, D.; Hecht, E.; Edwards, L.; Carey, S.; Bacon, M.; Futagaki, C.; Suk, D.; Tom, J.; Birnbaum, C.; Rork, A.

    2008-01-01

    Two electrophysiological studies tested the hypothesis that operant conditioning of mu rhythms via neurofeedback training can renormalize mu suppression, an index of mirror neuron activity, and improve behavior in children diagnosed with autism spectrum disorders (ASD). In Study 1, eight high-functioning ASD participants were assigned to placebo…

  7. Combined two-photon imaging, electrophysiological, and anatomical investigation of the human neocortex in vitro.

    Science.gov (United States)

    Kerekes, Bálint Péter; Tóth, Kinga; Kaszás, Attila; Chiovini, Balázs; Szadai, Zoltán; Szalay, Gergely; Pálfi, Dénes; Bagó, Attila; Spitzer, Klaudia; Rózsa, Balázs; Ulbert, István; Wittner, Lucia

    2014-07-01

    Spontaneous synchronous population activity (SPA) can be detected by electrophysiological methods in cortical slices of epileptic patients, maintained in a physiological medium in vitro. In order to gain additional spatial information about the network mechanisms involved in the SPA generation, we combined electrophysiological studies with two-photon imaging. Neocortical slices prepared from postoperative tissue of epileptic and tumor patients were maintained in a dual perfusion chamber in a physiological incubation medium. SPA was recorded with a 24-channel extracellular linear microelectrode covering all neocortical layers. After identifying the electrophysiologically active regions of the slice, bolus loading of neuronal and glial markers was applied on the tissue. SPA-related [Formula: see text] transients were detected in a large population of neighboring neurons with two-photon microscopy, simultaneous with extracellular SPA and intracellular whole-cell patch-clamp recordings. The intracellularly recorded cells were filled for subsequent anatomy. The cells were reconstructed in three dimensions and examined with light- and transmission electron microscopy. Combining high spatial resolution two-photon [Formula: see text] imaging techniques and high temporal resolution extra- and intracellular electrophysiology with cellular anatomy may permit a deeper understanding of the structural and functional properties of the human neocortex. PMID:26157969

  8. Electrophysiologic and antiarrhythmic effects of intravenous bisoprolol in atrioventricular nodal reentry tachycardia

    NARCIS (Netherlands)

    vandeVen, LLM; Crijns, HJGM; deMuinck, ED; VanGelder, IC; VanWijk, LM; Lie, KI

    1996-01-01

    Beta-blockade may be useful in the termination and prevention of atrioventricular nodal reentry tachycardia (AVNRT), An electrophysiologic study was performed in 9 patients (4 men and 5 women; mean +/- SD age, 56 +/- 16 years) with documented AVNRT before and after the intravenous administration of

  9. Serum cytokine contents in schizophrenia patient with metabolic syndrome and their correlation with nerve electrophysiology

    Institute of Scientific and Technical Information of China (English)

    Li-Yong Chen; Zhong Chen; Xue-Jing Li

    2016-01-01

    Objective:To analyze serum cytokine contents in schizophrenia patient with metabolic syndrome (MS) and their correlation with nerve electrophysiology.Methods:A total of 90 chizophrenia patient with MS, including 41 cases with simple schizophrenia and 39 cases with simple metabolic syndrome were included for study. The values of nerve electrophysiology indexes and serum illness-related indexes were compared among included patients, and the correlation between the two was further analyzed.Results:Compared with simple schizophrenia group and simple MS group, P300 latency of schizophrenia with MS group was longer, and the amplitude was shorter; N2-P3 latency and amplitude were shorter (P<0.05); serum SOD, S100b, BDNF, ABAb, PAI-1,α-HBDH, AST, cystatin c, TG, FBG and 2hPG values of schizophrenia with MS group were higher, IGF1, HMW-APN and HDL-C levels were lower, and compared with simple schizophrenia group and simple MS group, differences were significant (P<0.05); P300 latency, P300 amplitude, N2-P3 latency and N2-P3 amplitude of schizophrenia with MS group were directly correlated with serum cytokine contents (P<0.05).Conclusions:There are significantly abnormal serum cytokines and nerve electrophysiology indexes in schizophrenia patient with MS, and nerve electrophysiology detection can be used as the means to judge disease and guide treatment.

  10. NeuroElectro: A Window to the World's Neuron Electrophysiology Data

    Directory of Open Access Journals (Sweden)

    Shreejoy J Tripathy

    2014-04-01

    Full Text Available The behavior of neural circuits is determined largely by the electrophysiological properties of the neurons they contain. Understanding the relationships of these properties requires the ability to first identify and catalog each property. However, information about such properties is largely locked away in decades of closed-access journal articles with heterogeneous conventions for reporting results, making it difficult to utilize the underlying data. We solve this problem through the NeuroElectro project: a Python library, RESTful API, and web application (at http://neuroelectro.org for the extraction, visualization, and summarization of published data on neurons' electrophysiological properties. Information is organized both by neuron type (using neuron definitions provided by NeuroLex and by electrophysiological property (using a newly developed ontology. We describe the techniques and challenges associated with the automated extraction of tabular electrophysiological data and methodological metadata from journal articles. We further discuss strategies for how to best combine, normalize and organize data across these heterogeneous sources. NeuroElectro is a valuable resource for experimental physiologists looking to supplement their own data, for computational modelers looking to constrain their model parameters, and for theoreticians searching for undiscovered relationships among neurons and their properties.

  11. Electrophysiological correlates of associative visual agnosia lesioned in the ventral pathway.

    Science.gov (United States)

    Yamasaki, Takao; Taniwaki, Takayuki; Tobimatsu, Shozo; Arakawa, Kenji; Kuba, Hiroshi; Maeda, Yoshihisa; Kuwabara, Yasuo; Shida, Kenshiro; Ohyagi, Yasumasa; Yamada, Takeshi; Kira, Jun-ichi

    2004-06-15

    Visual agnosia has been well studied by anatomical, neuropsychological and neuroimaging studies. However, functional changes in the brain have been rarely assessed by electrophysiological methods. We carried out electrophysiological examinations on a 23-year-old man with associative visual agnosia, prosopagnosia and cerebral achromatopsia to evaluate the higher brain dysfunctions of visual recognition. Electrophysiological methods consisted of achromatic, chromatic and category-specific visual evoked potentials (CS-VEPs), and event-related potentials (ERPs) with color and motion discrimination tasks. Brain magnetic resonance imaging revealed large white matter lesions in the bilateral temporo-occipital lobes involving the lingual and fusiform gyri (V4) and inferior longitudinal fasciculi due to multiple sclerosis. Examinations including CS-VEPs demonstrated dysfunctions of face and object perception while sparing semantic word perception after primary visual cortex (V1) in the ventral pathway. ERPs showed abnormal color perception in the ventral pathway with normal motion perception in the dorsal pathway. These electrophysiological findings were consistent with lesions in the ventral pathway that were detected by clinical and neuroimaging findings. Therefore, CS-VEPs and ERPs with color and motion discrimination tasks are useful methods for assessing the functional changes of visual recognition such as visual agnosia.

  12. Agreement Mechanisms in Native and Nonnative Language Processing: Electrophysiological Correlates of Complexity and Interference

    Science.gov (United States)

    Tanner, Darren

    2011-01-01

    This dissertation investigates the neural and behavioral correlates of grammatical agreement computation during language comprehension in native English speakers and highly advanced L1 Spanish-L2 English bilinguals. In a series of electrophysiological (event-related brain potential (ERP)) and behavioral (acceptability judgment and self-paced…

  13. Electrophysiological Indices of Abnormal Error-Processing in Adolescents with Attention Deficit Hyperactivity Disorder (ADHD)

    Science.gov (United States)

    Groom, Madeleine J.; Cahill, John D.; Bates, Alan T.; Jackson, Georgina M.; Calton, Timothy G.; Liddle, Peter F.; Hollis, Chris

    2010-01-01

    Background: Impaired cognitive control has been frequently observed in children and young people with attention deficit hyperactivity disorder (ADHD) and might underlie the excessive hyperactivity and impulsivity in this population. We investigated behavioural and electrophysiological indices relevant to one domain of cognitive control; namely…

  14. A SUBSTRATE AND A METHOD FOR DETERMINING AND/OR MONITORING ELECTROPHYSIOLOGICAL PROPERTIES OF ION CHANNELS

    DEFF Research Database (Denmark)

    2001-01-01

    The present invention relates to a substrate and a method for obtaining an electrophysiological measuring configuration in which a cell forms a high resistive seal (giga-seal) around a measuring electrode making it suitable for determining and monitoring a current flow through the cell membrane...

  15. Wrist Ultrasonography vs. Electrophysiological Studies in the Diagnosis of Carpal Tunnel Syndrome

    Directory of Open Access Journals (Sweden)

    Amirhossein Hashemi Attar

    2009-01-01

    Full Text Available   "nIntroduction: The carpal tunnel syndrome (CTS is the most common entrapment neuropathy and is caused by compression of the median nerve in the carpal tunnel. It is characterized by pain or paresthesia in areas innervated by the median nerve. Electrophysiological studies are gold standard diagnostic tests for CTS. The objective of this study was to compare ultrasonography and electrophysiological studies in the diagnosis of CTS. "nMaterials and Methods: This cross sectional study was conducted on 100 wrists of 50 consecutive patients referred to 22-Bahman hospital (Mashhad with the clinical diagnosis of CTS from spring 2007 to summer 2008. These patients suspicious for CTS in at least one of their wrists (based on their complaints and neurological examination including Tinel’s test and Phallen test, were referred for electrophysiological studies including nerve conduction velocity and electromyography. All the patients underwent ultrasonography of both wrists within a week after electrophysiological studies. Ultrasonographies were performed by a radiologist using a high frequency (12 MHz linear probe (PHILIPS Envisor C. The cross sectional area of the median nerve was measured at the carpal tunnel. Measurements equal or more than 10 mm2 were considered as the CTS. Ultrasonographic findings and also clinical examination (Tinel’s test and Phalen’s test were compared with electrophysiological studies (as the gold standard diagnostic test for each wrist separately. "nResults: Of the 100 wrists (50 patients, 53 wrists were diagnosed as CTS based on the electrophysiological studies. Ninety one percent of the wrists with CTS were in female patients. The mean age was 52.1 years (23-75 years. There was no predisposing factor for most cases; however, 6% were affected by diabetes, 6% by hypertriglyceridemia, and 2% by hypothyroidism. The sensitivity, specificity and accuracy of clinical examination (Tinel’s test and Phalen’s test were 59%, 88

  16. Mathematical modeling of heterogeneous electrophysiological responses in human β-cells.

    Directory of Open Access Journals (Sweden)

    Michela Riz

    2014-01-01

    Full Text Available Electrical activity plays a pivotal role in glucose-stimulated insulin secretion from pancreatic β-cells. Recent findings have shown that the electrophysiological characteristics of human β-cells differ from their rodent counterparts. We show that the electrophysiological responses in human β-cells to a range of ion channels antagonists are heterogeneous. In some cells, inhibition of small-conductance potassium currents has no effect on action potential firing, while it increases the firing frequency dramatically in other cells. Sodium channel block can sometimes reduce action potential amplitude, sometimes abolish electrical activity, and in some cells even change spiking electrical activity to rapid bursting. We show that, in contrast to L-type Ca2+-channels, P/Q-type Ca2+-currents are not necessary for action potential generation, and, surprisingly, a P/Q-type Ca2+-channel antagonist even accelerates action potential firing. By including SK-channels and Ca2+ dynamics in a previous mathematical model of electrical activity in human β-cells, we investigate the heterogeneous and nonintuitive electrophysiological responses to ion channel antagonists, and use our findings to obtain insight in previously published insulin secretion measurements. Using our model we also study paracrine signals, and simulate slow oscillations by adding a glycolytic oscillatory component to the electrophysiological model. The heterogenous electrophysiological responses in human β-cells must be taken into account for a deeper understanding of the mechanisms underlying insulin secretion in health and disease, and as shown here, the interdisciplinary combination of experiments and modeling increases our understanding of human β-cell physiology.

  17. Electrophysiological Monitoring in Patients With Tumors of the Skull Base Treated by Carbon-12 Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Carozzo, Simone [Department of Neuroscience, Ophthalmology, and Genetics, University of Genova, Genova (Italy); Schardt, Dieter [Department of Biophysics, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); Narici, Livio [Department of Physics, University of Rome Tor Vergata, Rome (Italy); Combs, Stephanie E.; Debus, Jürgen [Department of Radiation Oncology, University of Heidelberg, Heidelberg (Germany); Sannita, Walter G., E-mail: wgs@dism.unige.it [Department of Neuroscience, Ophthalmology, and Genetics, University of Genova, Genova (Italy); Department of Psychiatry, State University of New York, Stony Brook, New York (United States)

    2013-03-15

    Purpose: To report the results of short-term electrophysiologic monitoring of patients undergoing {sup 12}C therapy for the treatment of skull chordomas and chondrosarcomas unsuitable for radical surgery. Methods and Materials: Conventional electroencephalogram (EEG) and retinal and cortical electrophysiologic responses to contrast stimuli were recorded from 30 patients undergoing carbon ion radiation therapy, within a few hours before the first treatment and after completion of therapy. Methodologies and procedures were compliant with the guidelines of the International Federation for Clinical Neurophysiology and International Society for Clinical Electrophysiology of Vision. Results: At baseline, clinical signs were reported in 56.6% of subjects. Electrophysiologic test results were abnormal in 76.7% (EEG), 78.6% (cortical evoked potentials), and 92.8% (electroretinogram) of cases, without correlation with neurologic signs, tumor location, or therapy plan. Results on EEG, but not electroretinograms and cortical responses, were more often abnormal in patients with reported clinical signs. Abnormal EEG results and retinal/cortical responses improved after therapy in 40% (EEG), 62.5% (cortical potentials), and 70% (electroretinogram) of cases. Results on EEG worsened after therapy in one-third of patients whose recordings were normal at baseline. Conclusions: The percentages of subjects whose EEG results improved or worsened after therapy and the improvement of retinal/cortical responses in the majority of patients are indicative of a limited or negligible (and possibly transient) acute central nervous system toxicity of carbon ion therapy, with a significant beneficial effect on the visual pathways. Research on large samples would validate electrophysiologic procedures as a possible independent test for central nervous system toxicity and allow investigation of the correlation with clinical signs; repeated testing over time after therapy would demonstrate, and may

  18. Serial electrophysiological findings in Guillain-Barré syndrome not fulfilling AIDP or AMAN criteria.

    Science.gov (United States)

    Hosokawa, Takafumi; Nakajima, Hideto; Unoda, Kiichi; Yamane, Kazushi; Doi, Yoshimitsu; Ishida, Shimon; Kimura, Fumiharu; Hanafusa, Toshiaki

    2016-09-01

    Guillain-Barré syndrome (GBS) is categorized into two major subtypes: acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN). However, a proportion of patients are electrophysiologically unclassified because of electrophysiological findings that do not fulfil AIDP or AMAN criteria, and underlying pathophysiological mechanisms and lesion distributions of unclassified patients are not well defined. The aims of this study are to elucidate disease pathophysiology and lesion distribution in unclassified patients. We retrospectively studied 48 consecutive GBS patients. Patients were classified on the basis of initial electrophysiological findings according to Ho's criteria. Clinical and serial electrophysiological examinations of unclassified patients were conducted. Twelve (25 %) GBS patients were unclassified. All unclassified patients were able to walk independently at 21 days after onset. No unclassified patients, except one patient with diabetes mellitus, had sensory nerve involvement. Eight patients underwent a follow-up study within 15 days of the initial study. Distal motor latencies (DMLs) of the left median motor nerve were found to be significantly and uniformly decreased compared with initial studies (p = 0.008). DMLs (p CMAP) durations (p = 0.002) of all nerves were significantly decreased, and distal CMAP amplitudes (p = 0.026) significantly increased compared with initial studies. In unclassified GBS patients, DML values during initial electrophysiological studies would be prolonged compared with expected values in the same patient unaffected by GBS and later improve rapidly with increased distal CMAP amplitudes without the development of excessive temporal dispersions. Lesions are also present in distal nerve segments caused by reversible conduction failure. PMID:27278064

  19. Cardiac MR imaging in arrhythmogenic heart diseases; Kardiale MRT in der Diagnostik arrhythmogener Herzerkrankungen

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, C.K.; Dinter, D.J.; Diehl, S.J.; Neff, K.W. [Universitaetsklinikum Mannheim, Institut fuer Klinische Radiologie, Mannheim (Germany); Papavassiliu, T.; Borggrefe, M. [Universitaetsklinikum Mannheim, Medizinische Klinik, Mannheim (Germany)

    2007-04-15

    Cardiac arrhythmias are assessed with a combination of history, clinical examination, electrocardiogram, Holter monitor, if necessary supplemented by invasive cardiac electrophysiology. In ischemic heart disease (IHD) coronary angiography is performed in addition. Echocardiography is usually the primary imaging modality. MRI is increasingly recognized as an important investigation allowing more accurate cardiac morphological and functional assessment. Approximately one-fifth of deaths in Western countries are due to sudden cardiac death, 80% of which are caused by arrhythmias. Typical causes range from diseases with high prevalence (IHD in men 30%) to myocarditis (prevalence 1-9%) and rare cardiomyopathies (prevalence HCM 0.2%, ARVC 0.02%, Brugada syndrome approx. 0.5%). The characteristic MRI features of arrhythmogenic diseases and the new aspects of characteristic distribution of late enhancement allow etiologic classification and differential diagnosis. MRI represents an important tool for detection of the underlying cause and for risk stratification in many diseases associated with arrhythmias. (orig.) [German] Herzrhythmusstoerungen werden durch die Zusammenschau von Anamnese, klinischer Untersuchung, Elektrokardiogramm, Langzeit-EKG sowie ggf. einer invasiven elektrophysiologischen Untersuchung beurteilt. Bei der koronaren Herzerkrankung (KHK) erfolgt zusaetzlich eine Koronarangiographie. Die Echokardiographie stellt das primaere bildgebende Verfahren dar. Die MRT des Herzens ermoeglicht eine genauere morphologische und funktionelle Darstellung des Herzens und gewinnt damit zunehmend an Bedeutung. Etwa jeder 5. Todesfall in westlichen Industriestaaten ist auf einen ploetzlichen Herztod zurueckzufuehren, davon sind ca. 80% durch Herzrhythmusstoerungen verursacht. Typische Ursachen reichen von Krankheiten mit hoher Praevalenz (KHK bei Maennern 30%) ueber Myokarditiden (Praevalenz 1-9%) bis zu selteneren Kardiomyopathien (Praevalenz HCM 0,2%, ARVC 0,02%, Brugada

  20. Mouse ECG findings in aging, with conduction system affecting drugs and in cardiac pathologies: Development and validation of ECG analysis algorithm in mice

    OpenAIRE

    Merentie, Mari; Jukka A Lipponen; Hedman, Marja; Hedman, Antti; Hartikainen, Juha; Huusko, Jenni; Lottonen‐Raikaslehto, Line; Parviainen, Viktor; Laidinen, Svetlana; KARJALAINEN, Pasi A.; Ylä‐Herttuala, Seppo

    2015-01-01

    Abstract Mouse models are extremely important in studying cardiac pathologies and related electrophysiology, but very few mouse ECG analysis programs are readily available. Therefore, a mouse ECG analysis algorithm was developed and validated. Surface ECG (lead II) was acquired during transthoracic echocardiography from C57Bl/6J mice under isoflurane anesthesia. The effect of aging was studied in young (2–3 months), middle‐aged (14 months) and old (20–24 months) mice. The ECG changes associat...

  1. Identification and Functional Characterization of a Novel CACNA1C-Mediated Cardiac Disorder Characterized by Prolonged QT Intervals with Hypertrophic Cardiomyopathy, Congenital Heart Defects, and Sudden Cardiac Death

    Science.gov (United States)

    Boczek, Nicole J.; Ye, Dan; Jin, Fang; Tester, David J.; Huseby, April; Bos, J. Martijn; Johnson, Aaron J.; Kanter, Ronald; Ackerman, Michael J.

    2016-01-01

    Background A portion of sudden cardiac deaths (SCD) can be attributed to structural heart diseases such as hypertrophic cardiomyopathy (HCM) or cardiac channelopathies such as long QT syndrome (LQTS); however, the underlying molecular mechanisms are quite distinct. Here, we identify a novel CACNA1C missense mutation with mixed loss-of-function/gain-of-function responsible for a complex phenotype of LQTS, HCM, SCD, and congenital heart defects (CHDs). Methods and Results Whole exome sequencing (WES) in combination with Ingenuity Variant Analysis was completed on three affected individuals and one unaffected individual from a large pedigree with concomitant LQTS, HCM, and CHDs and identified a novel CACNA1C mutation, p.Arg518Cys, as the most likely candidate mutation. Mutational analysis of exon 12 of CACNA1C was completed on 5 additional patients with a similar phenotype of LQTS plus a personal or family history of HCM-like phenotypes, and identified two additional pedigrees with mutations at the same position, p.Arg518Cys/His. Whole cell patch clamp technique was used to assess the electrophysiological effects of the identified mutations in CaV1.2, and revealed a complex phenotype, including loss of current density and inactivation in combination with increased window and late current. Conclusions Through WES and expanded cohort screening, we identified a novel genetic substrate p.Arg518Cys/His-CACNA1C, in patients with a complex phenotype including LQTS, HCM, and CHDs annotated as cardiac-only Timothy syndrome. Our electrophysiological studies, identification of mutations at the same amino acid position in multiple pedigrees, and co-segregation with disease in these pedigrees provides evidence that p.Arg518Cys/His is the pathogenic substrate for the observed phenotype. PMID:26253506

  2. MECANISMOS ELECTROFISIOLÓGICOS DE LA ELEVACIÓN DEL SEGMENTO ST DURANTE EL INFARTO AGUDO DE MIOCARDIO. HIPÓTESIS ACTUAL / Electrophysiological mechanisms of the st segment elevation during acute myocardial infarction. Current hypothesis

    Directory of Open Access Journals (Sweden)

    Raimundo Carmona Puerta

    2010-12-01

    Full Text Available Resumen El origen de la elevación del segmento ST elevado durante el infarto agudo de miocardio (IMA ha sido motivo de controversia. Con el avance de la electrofisiología cardíaca básica, hoy puede suponerse con alto grado de fiabilidad, las bases iónicas que generan la modificación del electrocardiograma clínico. A partir de una heterogeneidad eléctrica que existe en condiciones normales la isquemia miocárdica aguda, induce a una exacerbación de este comportamiento fisiológico y crea gradientes eléctricos transmurales significativos, que producen vectores potentes de corriente desde el endocardio al epicardio. Una respuesta diferente desde el punto de vista electrofisiológico, ante tal estímulo anormal, crea el sustrato funcional para tal discrepancia eléctrica a través del espesor de las paredes cardíacas. / Abstract The origin of the ST segment elevation during acute myocardial infarction (AMI has been the object of controversy. The advances in basic cardiac electrophysiology has made possible to assume, with a high degree of reliability, the ionic bases that generate the clinical electrocardiogram change. Starting from an electrical heterogeneity that exists in normal conditions, the acute myocardic ischemia induces an exacerbation of this physiological behavior and creates significant transmural electric gradients, which produces powerful electrical current vectors from the endocardium to the epicardium. A different response from the electrophysiological point of view, in the presence of such abnormal stimuli, creates a functional substratum for such an electric discrepancy through the thickness of the cardiac walls.

  3. Nutritional Status and Cardiac Autophagy

    Directory of Open Access Journals (Sweden)

    Jihyun Ahn

    2013-02-01

    Full Text Available Autophagy is necessary for the degradation of long-lasting proteins and nonfunctional organelles, and is activated to promote cellular survival. However, overactivation of autophagy may deplete essential molecules and organelles responsible for cellular survival. Lifelong calorie restriction by 40% has been shown to increase the cardiac expression of autophagic markers, which suggests that it may have a cardioprotective effect by decreasing oxidative damage brought on by aging and cardiovascular diseases. Although cardiac autophagy is critical to regulating protein quality and maintaining cellular function and survival, increased or excessive autophagy may have deleterious effects on the heart under some circumstances, including pressure overload-induced heart failure. The importance of autophagy has been shown in nutrient supply and preservation of energy in times of limitation, such as ischemia. Some studies have suggested that a transition from obesity to metabolic syndrome may involve progressive changes in myocardial inflammation, mitochondrial dysfunction, fibrosis, apoptosis, and myocardial autophagy.

  4. [Cardiac support and replacement therapies].

    Science.gov (United States)

    Lotz, Christopher; Roewer, Norbert; Muellenbach, Ralf M

    2016-09-01

    Circulatory support represents an integral part within the treatment of the critically ill patient. Sophisticated pharmacologic regimens help to maintain systemic perfusion pressure by increasing vascular tone as well as mediating positive inotropic effects. Besides the administration of catecholamines and phosphodiesterase-III-inhibitors, in particular the administration of levosimendan represents a promising alternative during low-cardiac-output. Nevertheless, sufficient evidence demonstrating a survival benefit for any pharmacologic regimen is nonexistent. In case pharmacological measures do not suffice mechanical cardiopulmonary support (MCS) may be used. MCS may be used during cardiopulmonary resuscitation or a "low-cardiac-output-syndrome" as bridging towards decision, recovery or long-term support. Venoarterial extracorporeal membrane oxygenation (vaECMO) may take over cardiopulmonary function and may improve survival as well as neurological outcome after cardiogenic shock or cardiopulmonary resuscitation. PMID:27631451

  5. Heart fields and cardiac morphogenesis.

    Science.gov (United States)

    Kelly, Robert G; Buckingham, Margaret E; Moorman, Antoon F

    2014-10-01

    In this review, we focus on two important steps in the formation of the embryonic heart: (i) the progressive addition of late differentiating progenitor cells from the second heart field that drives heart tube extension during looping morphogenesis, and (ii) the emergence of patterned proliferation within the embryonic myocardium that generates distinct cardiac chambers. During the transition between these steps, the major site of proliferation switches from progenitor cells outside the early heart to proliferation within the embryonic myocardium. The second heart field and ballooning morphogenesis concepts have major repercussions on our understanding of human heart development and disease. In particular, they provide a framework to dissect the origin of congenital heart defects and the regulation of myocardial proliferation and differentiation of relevance for cardiac repair.

  6. Cardiac Biomarkers in Hyperthyroid Cats

    OpenAIRE

    Sangster, J.K.; Panciera, D L; Abbott, J.A.; Zimmerman, K.C.; Lantis, A.C.

    2013-01-01

    Background Hyperthyroidism has substantial effects on the circulatory system. The cardiac biomarkers NT‐proBNP and troponin I (cTNI) have proven useful in identifying cats with myocardial disease but have not been extensively investigated in hyperthyroidism. Hypothesis Plasma NT‐proBNP and cTNI concentrations are higher in cats with primary myocardial disease than in cats with hyperthyroidism and higher in cats with hyperthyroidism than in healthy control cats. Animals Twenty‐three hyperthyro...

  7. Cardiac Biomarkers and Cycling Race

    OpenAIRE

    Caroline Le Goff, Jean-François Kaux, Sébastien Goffaux, Etienne Cavalier

    2015-01-01

    In cycling as in other types of strenuous exercise, there exists a risk of sudden death. It is important both to understand its causes and to see if the behavior of certain biomarkers might highlight athletes at risk. Many reports describe changes in biomarkers after strenuous exercise (Nie et al., 2011), but interpreting these changes, and notably distinguishing normal physiological responses from pathological changes, is not easy. Here we have focused on the kinetics of different cardiac bi...

  8. Cardiac involvement in tuberous sclerosis.

    OpenAIRE

    Mühler, E G; Turniski-Harder, V; Engelhardt, W.; von Bernuth, G

    1994-01-01

    OBJECTIVE--To assess the incidence, importance, and history of cardiac involvement in infants and children with tuberous sclerosis. DESIGN--Prospective study; clinical examination, sector and Doppler echocardiography, standard and ambulatory electrocardiography. SETTING--A tertiary referral centre. PATIENTS--21 patients with tuberous sclerosis aged 1 day to 16 years (mean 6.3 years); follow up investigations were available in 14 cases (10 retrospective, 4 prospective; mean follow up 4.3 years...

  9. Cardiac autonomic nerve distribution and arrhythmia

    Institute of Scientific and Technical Information of China (English)

    Quan Liu; Dongmei Chen; Yonggang Wang; Xin Zhao; Yang Zheng

    2012-01-01

    OBJECTIVE: To analyze the distribution characteristics of cardiac autonomic nerves and to explore the correlation between cardiac autonomic nerve distribution and arrhythmia.DATA RETRIEVAL: A computer-based retrieval was performed for papers examining the distribution of cardiac autonomic nerves, using "heart, autonomic nerve, sympathetic nerve, vagus nerve, nerve distribution, rhythm and atrial fibrillation" as the key words.SELECTION CRITERIA: A total of 165 studies examining the distribution of cardiac autonomic nerve were screened, and 46 of them were eventually included.MAIN OUTCOME MEASURES: The distribution and characteristics of cardiac autonomic nerves were observed, and immunohistochemical staining was applied to determine the levels of tyrosine hydroxylase and acetylcholine transferase (main markers of cardiac autonomic nerve distribution). In addition, the correlation between cardiac autonomic nerve distribution and cardiac arrhythmia was investigated.RESULTS: Cardiac autonomic nerves were reported to exhibit a disordered distribution in different sites, mainly at the surface of the cardiac atrium and pulmonary vein, forming a ganglia plexus. The distribution of the pulmonary vein autonomic nerve was prominent at the proximal end rather than the distal end, at the upper left rather than the lower right, at the epicardial membrane rather than the endocardial membrane, at the left atrium rather than the right atrium, and at the posterior wall rather than the anterior wall. The main markers used for cardiac autonomic nerves were tyrosine hydroxylase and acetylcholine transferase. Protein gene product 9.5 was used to label the immunoreactive nerve distribution, and the distribution density of autonomic nerves was determined using a computer-aided morphometric analysis system.CONCLUSION: The uneven distribution of the cardiac autonomic nerves is the leading cause of the occurrence of arrhythmia, and the cardiac autonomic nerves play an important role in the

  10. Sudden cardiac death risk stratification.

    Science.gov (United States)

    Deyell, Marc W; Krahn, Andrew D; Goldberger, Jeffrey J

    2015-06-01

    Arrhythmic sudden cardiac death (SCD) may be caused by ventricular tachycardia/fibrillation or pulseless electric activity/asystole. Effective risk stratification to identify patients at risk of arrhythmic SCD is essential for targeting our healthcare and research resources to tackle this important public health issue. Although our understanding of SCD because of pulseless electric activity/asystole is growing, the overwhelming majority of research in risk stratification has focused on SCD-ventricular tachycardia/ventricular fibrillation. This review focuses on existing and novel risk stratification tools for SCD-ventricular tachycardia/ventricular fibrillation. For patients with left ventricular dysfunction or myocardial infarction, advances in imaging, measures of cardiac autonomic function, and measures of repolarization have shown considerable promise in refining risk. Yet the majority of SCD-ventricular tachycardia/ventricular fibrillation occurs in patients without known cardiac disease. Biomarkers and novel imaging techniques may provide further risk stratification in the general population beyond traditional risk stratification for coronary artery disease alone. Despite these advances, significant challenges in risk stratification remain that must be overcome before a meaningful impact on SCD can be realized.

  11. Review Article of Cardiac Amyloidosis

    Directory of Open Access Journals (Sweden)

    Jittiporn PURATTANAMAL

    2010-06-01

    Full Text Available Cardiac amyloidosis is a term that means the deposit of abnormal proteins in the myocardium leading to global thickening of the heart walls. The clinical character is that of infiltrative cardiomyopathy. AL amyloidosis is the most common type that involves cardiac failure. Cardiac amyloid precedes clinical congestive heart failure, especially right-sided heart failure. Laboratory investigations have identified the amyloid fibril proteins deposited in the organ tissues. Immunofixation tests are the most sensitive that recognize the paraprotein mean light chain protein or immunoglobulin subtype deposit. Prognosis is poor if AL amyloidosis is untreated. Treatment of systemic involvement in AL amyloidosis is via chemotherapy such as melphalan and prednisolone. UK experts have reported the results of treatment in AL amyloidosis. Regardless of the use of adjunctive chemotherapy, the five-year survival after heart transplantation was generally poorer for AL (20 % at five years, but similar for non-AL amyloidosis (64 % at five years, than heart transplants in other cases. Progression of the systemic disease contributed to increased mortality. A specific treatment that increases the chances of survival is unknown.

  12. Cardiac MRI in restrictive cardiomyopathy

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, A. [Department of Cardiovascular Radiology, All India Institute of Medical Sciences, Ansari Nagar, Delhi (India); Singh Gulati, G., E-mail: gulatigurpreet@rediffmail.com [Department of Cardiovascular Radiology, All India Institute of Medical Sciences, Ansari Nagar, Delhi (India); Seth, S. [Department of Cardiology, All India Institute of Medical Sciences, Ansari Nagar, Delhi (India); Sharma, S. [Department of Cardiovascular Radiology, All India Institute of Medical Sciences, Ansari Nagar, Delhi (India)

    2012-02-15

    Restrictive cardiomyopathy (RCM) is a specific group of heart muscle disorders characterized by inadequate ventricular relaxation during diastole. This leads to diastolic dysfunction with relative preservation of systolic function. Although short axis systolic function is usually preserved in RCM, the long axis systolic function may be severely impaired. Confirmation of diagnosis and information regarding aetiology, extent of myocardial damage, and response to treatment requires imaging. Importantly, differentiation from constrictive pericarditis (CCP) is needed, as only the latter is managed surgically. Echocardiography is the initial cardiac imaging technique but cannot reliably suggest a tissue diagnosis; although recent advances, especially tissue Doppler imaging and spectral tracking, have improved its ability to differentiate RCM from CCP. Cardiac catheterization is the reference standard, but is invasive, two-dimensional, and does not aid myocardial characterization. Cardiac magnetic resonance (CMR) is a versatile technique providing anatomical, morphological and functional information. In recent years, it has been shown to provide important information regarding disease mechanisms, and also been found useful to guide treatment, assess its outcome and predict patient prognosis. This review describes the CMR features of RCM, appearances in various diseases, its overall role in patient management, and how it compares with other imaging techniques.

  13. Evaluation of Known or Suspected Cardiac Sarcoidosis.

    Science.gov (United States)

    Blankstein, Ron; Waller, Alfonso H

    2016-03-01

    Sarcoidosis is a multisystem disorder of unknown cause, and cardiac sarcoidosis affects at least 25% of patients and accounts for substantial mortality and morbidity from this disease. Cardiac sarcoidosis may present with heart failure, left ventricular systolic dysfunction, AV block, atrial or ventricular arrhythmias, and sudden cardiac death. Cardiac involvement can be challenging to detect and diagnose because of the focal nature of the disease, as well as the fact that clinical criteria have limited diagnostic accuracy. Nevertheless, the diagnosis of cardiac sarcoidosis can be enhanced by integrating both clinical and imaging findings. This article reviews the various roles that different imaging modalities provide in the evaluation and management of patients with known or suspected cardiac sarcoidosis. PMID:26926267

  14. Inheritance of electrophysiological responses to leaf saps of host- and nonhost plants in two helicoverpa species and their hybrids

    NARCIS (Netherlands)

    Tang, Q.B.; Huang, L.Q.; Wang, C.Z.; Tang, Q.B.T.; Zhan, H.; Loon, van J.J.A.

    2014-01-01

    The polyphagous cotton bollworm Helicoverpa armigera (Hubner) and the oligophagous oriental tobacco budworm Helicoverpa assulta (Guenee) (Lepidoptera: Noctuidae) display contrasting heritable feeding preferences for cotton and pepper leaves. In this study, electrophysiological response patterns to c

  15. An electrophysiological link between the cerebellum, cognition and emotion: Frontal theta EEG activity to single-pulse cerebellar TMS

    NARCIS (Netherlands)

    Schutter, D.J.L.G.; Honk, E.J. van

    2006-01-01

    Early intracranial electrical stimulation studies in animals demonstrated cerebellar connectivity to brain structures involved in cognitive and emotive functions. Human electrophysiological data to support cerebellum involvement in the latter functions are however lacking. In the present study, elec

  16. Sensing Cardiac Electrical Activity With a Cardiac Myocyte--Targeted Optogenetic Voltage Indicator

    NARCIS (Netherlands)

    Chang Liao, Mei-Ling; de Boer, Teun P; Mutoh, Hiroki; Raad, Nour; Richter, Claudia; Wagner, Eva; Downie, Bryan R; Unsöld, Bernhard; Arooj, Iqra; Streckfuss-Bömeke, Katrin; Döker, Stephan; Luther, Stefan; Guan, Kaomei; Wagner, Stefan; Lehnart, Stephan E; Maier, Lars S; Stühmer, Walter; Wettwer, Erich; van Veen, Toon; Morlock, Michael M; Knöpfel, Thomas; Zimmermann, Wolfram-Hubertus

    2015-01-01

    RATIONALE: Monitoring and controlling cardiac myocyte activity with optogenetic tools offer exciting possibilities for fundamental and translational cardiovascular research. Genetically encoded voltage indicators may be particularly attractive for minimal invasive and repeated assessments of cardiac

  17. Development of planar patch clamp technology and its application in the analysis of cellular electrophysiology

    Institute of Scientific and Technical Information of China (English)

    Peihua Chen; Wei Zhang; Jun Zhou; Ping Wang; Lidan Xiao; Mo Yang

    2009-01-01

    A patch clamp chip, as a novel cell-based chip for electrophysiological recordings, has many prominent advantages such as high res-olution, accuracy, high throughput and automation. It can be used to perform multivariate and real-time measurements of cell networks in situ. Therefore, this technology will dramatically promote the research on ionic channels, neuronal networks and the application of this technology in drug screening. This paper reviews the development of planar patch clamp technology and its applications in detail. The latest progress in the research of taste cells electrophysiology and taste transduction is also presented. Finally, this paper analyzes the methodology of neural chips. Based on the current research of our laboratory, the prospective applications of a patch clamp chip in the research of taste sensation and transduction mechanisms at molecular and cellular levels are discussed.

  18. Age-dependent changes in cat masseter nerve: an electrophysiological and morphological study.

    Science.gov (United States)

    Chase, M H; Engelhardt, J K; Adinolfi, A M; Chirwa, S S

    1992-07-24

    The present study was undertaken to determine the manner in which aging affects the function and structure of the masseter nerve in old cats. Electrophysiological data demonstrated a significant decrease in the conduction velocity of the action potential in old cats compared with that observed in adult cats. Light microscopic analyses revealed an age-dependent decrease in axon diameter. Electron microscopic observations of the masseter nerve in the aged cats revealed a disruption of the myelin sheaths and a pronounced increase in collagen fibers in the endoneurium and perineurium. These morphological changes are discussed and then related to the decrease in conduction velocity which was observed in the electrophysiological portion of this study. PMID:1521161

  19. Human T cells in silico: Modelling their electrophysiological behaviour in health and disease.

    Science.gov (United States)

    Ehling, Petra; Meuth, Patrick; Eichinger, Paul; Herrmann, Alexander M; Bittner, Stefan; Pawlowski, Matthias; Pankratz, Susann; Herty, Michael; Budde, Thomas; Meuth, Sven G

    2016-09-01

    Although various types of ion channels are known to have an impact on human T cell effector functions, their exact mechanisms of influence are still poorly understood. The patch clamp technique is a well-established method for the investigation of ion channels in neurons and T cells. However, small cell sizes and limited selectivity of pharmacological blockers restrict the value of this experimental approach. Building a realistic T cell computer model therefore can help to overcome these kinds of limitations as well as reduce the overall experimental effort. The computer model introduced here was fed off ion channel parameters from literature and new experimental data. It is capable of simulating the electrophysiological behaviour of resting and activated human CD4(+) T cells under basal conditions and during extracellular acidification. The latter allows for the very first time to assess the electrophysiological consequences of tissue acidosis accompanying most forms of inflammation. PMID:27288542

  20. First human trials of a dry electrophysiology sensor using a carbon nanotube array interface

    CERN Document Server

    Ruffini, G; Fuentemilla, L; Grau, C; Farres, E; Marco-Pallares, J; Watts, P C P; Silva, S R P

    2007-01-01

    Fatigue, sleepiness and disturbed sleep are important factors in health and safety in modern society and there is considerable interest in developing technologies for routine monitoring of associated physiological indicators. Electrophysiology, the measurement of the electrical activity of biological origin, is a key technique for the measurement of physiological parameters in several applications, but it has been traditionally difficult to develop sensors for measurements outside the laboratory or clinic with the required quality and robustness. In this paper we report the results from first human experiments using a new electrophysiology sensor called ENOBIO, using carbon nanotube arrays for penetration of the outer layers of the skin and improved electrical contact. These tests, which have included traditional protocols for the analysis of the electrical activity of the brain--spontaneous EEG and ERP--indicate performance on a par with state of the art research-oriented wet electrodes, suggesting that the ...

  1. Solid-state NMR, electrophysiology and molecular dynamics characterization of human VDAC2

    Energy Technology Data Exchange (ETDEWEB)

    Gattin, Zrinka; Schneider, Robert; Laukat, Yvonne; Giller, Karin [Max Planck Institute for Biophysical Chemistry (Germany); Maier, Elke [Theodor-Boveri-Institut (Biozentrum) der Universität Würzburg, Lehrstuhl für Biotechnologie (Germany); Zweckstetter, Markus; Griesinger, Christian [Max Planck Institute for Biophysical Chemistry (Germany); Benz, Roland [Theodor-Boveri-Institut (Biozentrum) der Universität Würzburg, Lehrstuhl für Biotechnologie (Germany); Becker, Stefan; Lange, Adam, E-mail: alange@fmp-berlin.de [Max Planck Institute for Biophysical Chemistry (Germany)

    2015-04-15

    The voltage-dependent anion channel (VDAC) is the most abundant protein of the outer mitochondrial membrane and constitutes the major pathway for the transport of ADP, ATP, and other metabolites. In this multidisciplinary study we combined solid-state NMR, electrophysiology, and molecular dynamics simulations, to study the structure of the human VDAC isoform 2 in a lipid bilayer environment. We find that the structure of hVDAC2 is similar to the structure of hVDAC1, in line with recent investigations on zfVDAC2. However, hVDAC2 appears to exhibit an increased conformational heterogeneity compared to hVDAC1 which is reflected in broader solid-state NMR spectra and less defined electrophysiological profiles.

  2. Automated segmentation and reconstruction of patient-specific cardiac anatomy and pathology from in vivo MRI

    International Nuclear Information System (INIS)

    This paper presents an automated method to segment left ventricle (LV) tissues from functional and delayed-enhancement (DE) cardiac magnetic resonance imaging (MRI) scans using a sequential multi-step approach. First, a region of interest (ROI) is computed to create a subvolume around the LV using morphological operations and image arithmetic. From the subvolume, the myocardial contours are automatically delineated using difference of Gaussians (DoG) filters and GSV snakes. These contours are used as a mask to identify pathological tissues, such as fibrosis or scar, within the DE-MRI. The presented automated technique is able to accurately delineate the myocardium and identify the pathological tissue in patient sets. The results were validated by two expert cardiologists, and in one set the automated results are quantitatively and qualitatively compared with expert manual delineation. Furthermore, the method is patient-specific, performed on an entire patient MRI series. Thus, in addition to providing a quick analysis of individual MRI scans, the fully automated segmentation method is used for effectively tagging regions in order to reconstruct computerized patient-specific 3D cardiac models. These models can then be used in electrophysiological studies and surgical strategy planning. (paper)

  3. Multicellular automaticity of cardiac cell monolayers: effects of density and spatial distribution of pacemaker cells

    Science.gov (United States)

    Elber Duverger, James; Boudreau-Béland, Jonathan; Le, Minh Duc; Comtois, Philippe

    2014-11-01

    Self-organization of pacemaker (PM) activity of interconnected elements is important to the general theory of reaction-diffusion systems as well as for applications such as PM activity in cardiac tissue to initiate beating of the heart. Monolayer cultures of neonatal rat ventricular myocytes (NRVMs) are often used as experimental models in studies on cardiac electrophysiology. These monolayers exhibit automaticity (spontaneous activation) of their electrical activity. At low plated density, cells usually show a heterogeneous population consisting of PM and quiescent excitable cells (QECs). It is therefore highly probable that monolayers of NRVMs consist of a heterogeneous network of the two cell types. However, the effects of density and spatial distribution of the PM cells on spontaneous activity of monolayers remain unknown. Thus, a simple stochastic pattern formation algorithm was implemented to distribute PM and QECs in a binary-like 2D network. A FitzHugh-Nagumo excitable medium was used to simulate electrical spontaneous and propagating activity. Simulations showed a clear nonlinear dependency of spontaneous activity (occurrence and amplitude of spontaneous period) on the spatial patterns of PM cells. In most simulations, the first initiation sites were found to be located near the substrate boundaries. Comparison with experimental data obtained from cardiomyocyte monolayers shows important similarities in the position of initiation site activity. However, limitations in the model that do not reflect the complex beat-to-beat variation found in experiments indicate the need for a more realistic cardiomyocyte representation.

  4. Echocardiography to magnetic resonance image registration for use in image-guided cardiac catheterization procedures

    Energy Technology Data Exchange (ETDEWEB)

    Ma Yingliang; Penney, Graeme P; Razavi, Reza; Rhode, Kawal S [Division of Imaging Sciences, King' s College, London SE1 7EH (United Kingdom); Rinaldi, C Aldo; Cooklin, Mike [Department of Cardiology, Guy' s and St Thomas' NHS Foundation Trust, London, SE1 7EH (United Kingdom)], E-mail: y.ma@kcl.ac.uk

    2009-08-21

    We present a robust method to register three-dimensional echocardiography (echo) images to magnetic resonance images (MRI) based on anatomical features, which is designed to be used in the registration pipeline for overlaying MRI-derived roadmaps onto two-dimensional live x-ray images during cardiac catheterization procedures. The features used in image registration are the endocardial surface of the left ventricle and the centre line of the descending aorta. The MR-derived left ventricle surface is generated using a fully automated algorithm, and the echo-derived left ventricle surface is produced using a semi-automatic segmentation method provided by the QLab software (Philips Healthcare) that it is routinely used in clinical practice. We test our method on data from six volunteers and four patients. We validated registration accuracy using two methods: the first calculated a root mean square distance error using expert identified anatomical landmarks, and the second method used catheters as landmarks in two clinical electrophysiology procedures. Results show a mean error of 4.1 mm, which is acceptable for our clinical application, and no failed registrations were observed. In addition, our algorithm works on clinical data, is fast and only requires a small amount of manual input, and so it is applicable for use during cardiac catheterization procedures.

  5. Enhanced QSAR models for drug-triggered inhibition of the main cardiac ion currents.

    Science.gov (United States)

    Wiśniowska, Barbara; Mendyk, Aleksander; Szlęk, Jakub; Kołaczkowski, Michał; Polak, Sebastian

    2015-09-01

    The currently changing cardiac safety testing paradigm suggests, among other things, a shift towards using in silico models of cellular electrophysiology and assessment of a concomitant block of multiple ion channels. In this study, a set of four enhanced QSAR models have been developed: for the rapid delayed rectifying potassium current (IKr), slow delayed rectifying potassium current (IKs), peak sodium current (INa) and late calcium current (ICaL), predicting ion currents changes for the specific in vitro experiment from the 2D structure of the compounds. The models are a combination of both in vitro study parameters and physico-chemical descriptors, which is a novel approach in drug-ion channels interactions modeling. Their predictive power assessed in the enhanced, more demanding than standard procedure, 10-fold cross validation was reasonably high. Rough comparison with published pure in silico hERG interaction models shows that the quality of the model predictions does not differ from other models available in the public domain, however, it takes its advantage in accounting for inter-experimental settings variability. Developed models are implemented in the Cardiac Safety Simulator, a commercially available platform enabling the in vitro-in vivo extrapolation of the drugs proarrhythmic effect and ECG simulation. A more comprehensive assessment of the effects of the compounds on ion channels allows for making more informed decisions regarding the risk - and thus avoidance - of exclusion of potentially safe and effective drugs. PMID:25559930

  6. Model-based imaging of cardiac electrical function in human atria

    Science.gov (United States)

    Modre, Robert; Tilg, Bernhard; Fischer, Gerald; Hanser, Friedrich; Messnarz, Bernd; Schocke, Michael F. H.; Kremser, Christian; Hintringer, Florian; Roithinger, Franz

    2003-05-01

    Noninvasive imaging of electrical function in the human atria is attained by the combination of data from electrocardiographic (ECG) mapping and magnetic resonance imaging (MRI). An anatomical computer model of the individual patient is the basis for our computer-aided diagnosis of cardiac arrhythmias. Three patients suffering from Wolff-Parkinson-White syndrome, from paroxymal atrial fibrillation, and from atrial flutter underwent an electrophysiological study. After successful treatment of the cardiac arrhythmia with invasive catheter technique, pacing protocols with stimuli at several anatomical sites (coronary sinus, left and right pulmonary vein, posterior site of the right atrium, right atrial appendage) were performed. Reconstructed activation time (AT) maps were validated with catheter-based electroanatomical data, with invasively determined pacing sites, and with pacing at anatomical markers. The individual complex anatomical model of the atria of each patient in combination with a high-quality mesh optimization enables accurate AT imaging, resulting in a localization error for the estimated pacing sites within 1 cm. Our findings may have implications for imaging of atrial activity in patients with focal arrhythmias.

  7. Image-Based Personalization of Cardiac Anatomy for Coupled Electromechanical Modeling.

    Science.gov (United States)

    Crozier, A; Augustin, C M; Neic, A; Prassl, A J; Holler, M; Fastl, T E; Hennemuth, A; Bredies, K; Kuehne, T; Bishop, M J; Niederer, S A; Plank, G

    2016-01-01

    Computational models of cardiac electromechanics (EM) are increasingly being applied to clinical problems, with patient-specific models being generated from high fidelity imaging and used to simulate patient physiology, pathophysiology and response to treatment. Current structured meshes are limited in their ability to fully represent the detailed anatomical data available from clinical images and capture complex and varied anatomy with limited geometric accuracy. In this paper, we review the state of the art in image-based personalization of cardiac anatomy for biophysically detailed, strongly coupled EM modeling, and present our own tools for the automatic building of anatomically and structurally accurate patient-specific models. Our method relies on using high resolution unstructured meshes for discretizing both physics, electrophysiology and mechanics, in combination with efficient, strongly scalable solvers necessary to deal with the computational load imposed by the large number of degrees of freedom of these meshes. These tools permit automated anatomical model generation and strongly coupled EM simulations at an unprecedented level of anatomical and biophysical detail. PMID:26424476

  8. Methods in pharmacology: measurement of cardiac output

    OpenAIRE

    Geerts, Bart F; Aarts, Leon P; Jansen, Jos R.

    2011-01-01

    Many methods of cardiac output measurement have been developed, but the number of methods useful for human pharmacological studies is limited. The ‘holy grail’ for the measurement of cardiac output would be a method that is accurate, precise, operator independent, fast responding, non-invasive, continuous, easy to use, cheap and safe. This method does not exist today. In this review on cardiac output methods used in pharmacology, the Fick principle, indicator dilution techniques, arterial pul...

  9. Cardiac tumours simulating collagen vascular disease.

    OpenAIRE

    Fitzpatrick, A. P.; Lanham, J. G.; Doyle, D V

    1986-01-01

    Cardiac tumours can mimic collagen vascular disease and they are often accompanied by profound systemic upset. Both benign and malignant tumours may present in this way. Three cases of cardiac tumour, two malignant and one benign, are reported with just such a presentation. A review of fifteen similar case reports showed that a spectrum of different collagen vascular diseases was diagnosed and treated before the true diagnosis emerged. In half of these cases the cardiac tumour was only diagno...

  10. Disseminated cysticercosis with pulmonary and cardiac involvement

    OpenAIRE

    Jain Bharat; Sankhe Shilpa; Agrawal Mukta; Naphade Prashant

    2010-01-01

    Pulmonary and cardiac involvement by cysticercosis is extremely rare, and is usually asymptomatic. We report the case of a 19-year-old boy who presented with a history of headache and vomiting and was found to have disseminated cysticercosis with pulmonary and cardiac involvement; the emphasis is on the rare occurrence of pulmonary, cardiac, pancreatic, intraocular, and extradural spinal canal involvement in the same patient. This case demonstrates the extent to which cysticercosis can be dis...

  11. Electrocardiographically Determination of Cardiac Enlargements in Dogs

    OpenAIRE

    Gönül, Remzi; OR, Mehmet Erman; DODURKA, Tamer

    2002-01-01

    In this study, the electrocardiographic parameters necessary to determine cardiac enlargements and to establish and distinguish such complaints from each other in the early stage in dogs with circulatory problems were assessed. The material of the study consisted of 33 dogs 1.5-15 years of age with cardiac enlargements determined from 140 dogs suspected of having cardiac disease based on clinical, radiographic and electrocardiographic analyses. In these dogs, 12 cases of left atrial hypert...

  12. Foot neuropathy in rheumatoid arthritis patients: clinical, electrophysiological, and ultrasound studies

    Directory of Open Access Journals (Sweden)

    Abd El-Samad I El-Hewala

    2016-01-01

    Conclusion Peripheral nerve affection is common in the rheumatoid foot, irrespective of the disease activity status. The most common neuropathies were posterior tarsal tunnel syndrome, peroneal nerve entrapment at the fibular neck, and pure sensory axonal neuropathy. A positive power Doppler signal and bone erosions of the ankle joint, detected by MSUS, were associated with RA disease activity. Electrophysiology was superior to MSUS for the diagnosis of posterior tarsal tunnel syndrome.

  13. Basic electrophysiological properties of spinal cord motoneurons during old age in the cat.

    Science.gov (United States)

    Morales, F R; Boxer, P A; Fung, S J; Chase, M H

    1987-07-01

    1. The electrophysiological properties of alpha-motoneurons in old cats (14-15 yr) were compared with those of adult cats (1-3 yr). These properties were measured utilizing intracellular recording and stimulating techniques. 2. Unaltered in the old cat motoneurons were the membrane potential, action potential amplitude, and slopes of the initial segment (IS) and soma dendritic (SD) spikes, as well as the duration and amplitude of the action potential's afterhyperpolarization. 3. In contrast, the following changes in the electrophysiological properties of lumbar motoneurons were found in the old cats: a decrease in axonal conduction velocity, a shortening of the IS-SD delay, an increase in input resistance, and a decrease in rheobase. 4. In spite of these considerable changes in motoneuron properties in the old cat, normal correlations between different electrophysiological properties were maintained. The following key relationships, among others, were the same in adult and old cat motoneurons: membrane potential polarization versus action potential amplitude, duration of the afterhyperpolarization versus motor axon conduction velocity, and rheobase versus input conductance. 5. A review of the existing literature reveals that neither chronic spinal cord section nor deafferentation (13, 21) in adult animals produce the changes observed in old cats. Thus we consider it unlikely that a loss of synaptic contacts was responsible for the modifications in electrophysiological properties observed in old cat motoneurons. 6. We conclude that during old age there are significant changes in the soma-dendritic portion of cat motoneurons, as indicated by the modifications found in input resistance, rheobase, and IS-SD delay, as well as significant changes in their axons, as indicated by a decrease in conduction velocity. PMID:3612223

  14. Leptin modulates electrophysiological characteristics and isoproterenol-induced arrhythmogenesis in atrial myocytes

    OpenAIRE

    Lin, Yung-Kuo; Chen, Yao-Chang; Huang, Jen-Hung; Lin, Yenn-Jiang; Huang, Shiang-Suo; Chen, Shih-Ann; Chen, Yi-Jen

    2013-01-01

    Background Obesity is an important risk factor for atrial fibrillation (AF). Leptin is an important adipokine. However, it is not clear whether leptin directly modulates the electrophysiological characteristics of atrial myocytes. Results Whole cell patch clamp and indo-1 fluorescence were used to record the action potentials (APs) and ionic currents in isolated rabbit left atrial (LA) myocytes incubated with and without (control) leptin (100 nM) for 1 h to investigate the role of leptin on a...

  15. The Electrophysiological Signature of Motivational Salience in Mice and Implications for Schizophrenia

    OpenAIRE

    Moessnang, Carolin; Habel, Ute; Schneider, Frank; Siegel, Steven J.

    2012-01-01

    According to the aberrant-salience hypothesis, attribution of motivational salience is severely disrupted in patients with schizophrenia. To provide a translational approach for investigating underlying mechanisms, neural correlates of salience attribution were examined in normal mice and in a MK-801 model of schizophrenia. Electrophysiological responses to standard and deviant tones were assessed in the medial prefrontal cortex (mPFC) using an auditory oddball paradigm. Motivational salience...

  16. Shaolin Dan Tian Breathing Fosters Relaxed and Attentive Mind: A Randomized Controlled Neuro-Electrophysiological Study

    OpenAIRE

    Agnes S. Chan; Mei-Chun Cheung; Sze, Sophia L.; Winnie Wing-Man Leung; Dejian Shi

    2011-01-01

    Neuro-electrophysiological studies on meditative breathing revealed its association with either a relaxed or an attentive state. The present study aimed to investigate whether the Shaolin Dan Tian Breathing (DTB) technique, which consists of the Passive and Active subtypes and can be considered as a relaxation exercise and Qigong, would induce both relaxed and attentive states. Twenty-two adults and 22 age-, gender- and education-matched controls received training on the Shaoli...

  17. Brain-wide analysis of electrophysiological diversity yields novel categorization of mammalian neuron types

    OpenAIRE

    Tripathy, Shreejoy J.; Shawn D Burton; Geramita, Matthew; Gerkin, Richard C.; Nathaniel N Urban

    2015-01-01

    For decades, neurophysiologists have characterized the biophysical properties of a rich diversity of neuron types. However, identifying common features and computational roles shared across neuron types is made more difficult by inconsistent conventions for collecting and reporting biophysical data. Here, we leverage NeuroElectro, a literature-based database of electrophysiological properties (www.neuroelectro.org), to better understand neuronal diversity, both within and across neuron types,...

  18. Intrinsic Electrophysiology of Mouse Corticospinal Neurons: a Class-Specific Triad of Spike-Related Properties

    OpenAIRE

    Benjamin A Suter; Migliore, Michele; Gordon M. G Shepherd

    2012-01-01

    Corticospinal pyramidal neurons mediate diverse aspects of motor behavior. We measured spike-related electrophysiological properties of identified corticospinal neurons in primary motor cortex slices from young adult mice. Several consistent features were observed in the suprathreshold responses to current steps: 1) Corticospinal neurons fired relatively fast action potentials (APs; width at half-maximum 0.65 ± 0.13 ms, mean ± standard deviation [SD]) compared with neighboring callosally proj...

  19. Paying attention to attention in recognition memory: Insights from models and electrophysiology

    OpenAIRE

    Dube, Chad; Payne, Lisa; Sekuler, Robert; Rotello, Caren M.

    2013-01-01

    Reliance on remembered facts or events requires memory for their sources, that is, the contexts in which those facts or events were embedded. Understanding of source retrieval has been stymied by the fact that uncontrolled fluctuations of attention during encoding can cloud important distinctions between competing theoretical accounts. To clarify the issue, we combined electrophysiology (high-density EEG recordings) with computational modeling of behavioral results. We manipulated subjects’ a...

  20. Hypoglossal-facial nerve anastomosis: a clinical and electrophysiological follow-up.

    OpenAIRE

    Iansek, R.; Harrison, M. J.; Andrew, J

    1986-01-01

    Eight patients with acoustic neuroma and five patients with hemifacial spasm, who had undergone hypoglossal-facial nerve anastomosis 1-14 years previously, were reviewed clinically and electrophysiologically with an electrically elicited blink reflex. Functional recovery from the anastomosis, as rigorously judged on a scale of good, fair and poor, was fair to poor. Electrically it was found that the blink reflex was present in eight patients, suggesting facial nerve re-innervation of the faci...

  1. Pyramidal cell development: postnatal spinogenesis, dendritic growth, axon growth, and electrophysiology.

    Directory of Open Access Journals (Sweden)

    Guy eElston

    2014-08-01

    Full Text Available Here we review recent findings related to postnatal spinogenesis, dendritic and axon growth, pruning and electrophysiology of neocortical pyramidal cells in the developing primate brain. Pyramidal cells in sensory, association and executive cortex grow dendrites, spines and axons at different rates, and vary in the degree of pruning. Of particular note is the fact that pyramidal cells in primary visual area (V1 prune more spines than they grow during postnatal development, whereas those in inferotemporal (TEO and TE and granular prefrontal cortex (gPFC; Brodmann’s area 12 grow more than they prune. Moreover, pyramidal cells in TEO, TE and the gPFC continue to grow larger dendritic territories from birth into adulthood, replete with spines, whereas those in V1 become smaller during this time. The developmental profile of intrinsic axons also varies between cortical areas: those in V1, for example, undergo an early proliferation followed by pruning and local consolidation into adulthood, whereas those in area TE tend to establish their territory and consolidate it into adulthood with little pruning. We correlate the anatomical findings with the electrophysiological properties of cells in the different cortical areas, including membrane time constant, depolarizing sag, duration of individual action potentials, and spike-frequency adaptation. All of the electrophysiological variables ramped up before 7 months of age in V1, but continued to ramp up over a protracted period of time in area TE. These data suggest that the anatomical and electrophysiological profiles of pyramidal cells vary among cortical areas at birth, and continue to diverge into adulthood. Moreover, the data reveal that the use it or lose it notion of synaptic reinforcement may speak to only part of the story, use it but you still might lose it may be just as prevalent in the cerebral cortex.

  2. Insulin-Induced Electrophysiology Changes in Human Pleura Are Mediated via Its Receptor

    OpenAIRE

    V. K. Kouritas; Ioannou, M.; Foroulis, C. N.; Desimonas, N.; K. Evaggelopoulos; Gourgoulianis, K. I.; Molyvdas, P A; Hatzoglou, C.

    2010-01-01

    Background. Insulin directly changes the sheep pleural electrophysiology. The aim of this study was to investigate whether insulin induces similar effects in human pleura, to clarify insulin receptor's involvement, and to demonstrate if glibenclamide (hypoglycemic agent) reverses this effect. Methods. Human parietal pleural specimens were mounted in Ussing chambers. Solutions containing insulin or glibenclamide and insulin with anti-insulin antibody, anti-insulin receptor antibody, and gl...

  3. Closed-Loop, Multichannel Experimentation Using the Open-Source NeuroRighter Electrophysiology Platform

    OpenAIRE

    Jonathan Paul Newman; Riley Zeller-Townson; Ming-fai Fong; Sharanya Arcot Desai; Gross, Robert E.; Potter, Steve M.

    2013-01-01

    Single neuron feedback control techniques, such as voltage clamp and dynamic clamp, have enabled numerous advances in our understanding of ion channels, electrochemical signaling, and neural dynamics. Although commercially available multichannel recording and stimulation systems are commonly used for studying neural processing at the network level, they provide little native support for real-time feedback. We developed the open-source NeuroRighter multichannel electrophysiology hardware and s...

  4. OpenElectrophy: An Electrophysiological Data- and Analysis-Sharing Framework

    OpenAIRE

    Samuel Garcia; Nicolas Fourcaud-Trocmé

    2009-01-01

    Progress in experimental tools and design is allowing the acquisition of increasingly large datasets. Storage, manipulation and efficient analyses of such large amounts of data is now a primary issue. We present OpenElectrophy, an electrophysiological data and analysis sharing framework developed to fill this niche. Based on the object-oriented language Python, it stores all experiment data and meta-data in a single central SQL-type database. It also provides a graphic user interface to visua...

  5. Electrophysiological correlates of emotional face processing in typically developing adults and adults with high functioning Autism

    OpenAIRE

    Barrie, Jennifer Nicole

    2012-01-01

    Emotional expressions have been found to affect various event-related potentials (ERPs). Furthermore, socio-emotional functioning is altered in individuals with autism, and a growing body of neuroimaging and electrophysiological evidence substantiates underlying neural differences for face processing in this population. However, relatively few studies have examined the time-course of emotional face processing in autism. This study examined how implicit (not the intended focus of attention) ve...

  6. Spasticity and Electrophysiologic Changes after Extracorporeal Shock Wave Therapy on Gastrocnemius

    OpenAIRE

    Sohn, Min Kyun; Cho, Kang Hee; Kim, Young-Jae; Hwang, Seon Lyul

    2011-01-01

    Objective To evaluate the spasticity and electrophysiologic effects of applying extracorporeal shock wave therapy (ESWT) to the gastrocnemius by studying F wave and H-reflex. Method Ten healthy adults and 10 hemiplegic stroke patients with ankle plantarflexor spasticity received one session of ESWT on the medial head of the gastrocnemius. The modified Ashworth scale (MAS), tibial nerve conduction, F wave, and H-reflex results were measured before and immediately after the treatment. The Visua...

  7. Visual and spatial modulation of tactile extinction: behavioural and electrophysiological evidence

    OpenAIRE

    Chiara Francesca Sambo; Giuseppe eVallar; Paola eFortis; Roberta eRonchi; Lucio ePosteraro; Bettina eForster; Angelo eMaravita

    2012-01-01

    Crossing the hands over the midline reduces left tactile extinction to double simultaneous stimulation in right-brain-damaged patients, suggesting that spatial attentional biases toward the ipsilesional (right) side of space contribute to the patients' contralesional (left) deficit. We investigated (1) whether the position of the left hand, and its vision, affected processing speed of tactile stimuli, and (2) the electrophysiological underpinnings of the effect of hand position. (1) Four righ...

  8. A Behavioural and Electrophysiological exploration of the Working Memory impairment in Developmental Dyslexia

    OpenAIRE

    Ahmad, Jumana

    2015-01-01

    The current thesis provides a behavioural and electrophysiological exploration of Working Memory (WM) processing in developmental dyslexia. This thesis identifies a debate in the literature regarding the extent to which individuals with dyslexia have a specific phonological WM impairment, or a domain general Central Executive (CE) impairment. Predictions from the latter account suggest that dyslexics should show an impairment in visual, and verbal domains of WM. However, findings in the visua...

  9. Electrophysiology of Intuition: Pre-stimulus Responses in Group and Individual Participants Using a Roulette Paradigm

    OpenAIRE

    McCraty, Rollin; Atkinson, Mike

    2014-01-01

    This study used electrophysiological measures of pre-stimulus effects that can occur prior to an unknown future event as an indicator of nonlocal intuition. Intuition in this context is considered as a process by which information normally outside the range of conscious awareness is detected at the cellular level by the heart, the brain, and the autonomic nervous system. This study extends the findings of previous experiments demonstrating that aspects of our physiology can respond to an emot...

  10. Effect of Rejection on Electrophysiologic Function of Canine Intestinal Grafts: Correlation with Histopathology and Na–K-ATPase Activity

    OpenAIRE

    Takeyoshi, Izumi; Zhang, Shimin; KOKUDO, YASUTAKA; Kenjiro NAKAMURA; Ikoma, Akira; Zhu, Yue; Starzl, Thomas E.; Todo, Satoru

    1995-01-01

    To investigate whether electrophysiologic changes can detect the early onset and progress of intestinal rejection, changes in in vitro electrophysiologic function, intestinal histopathology, and Na–K-ATPase activity were studied in dogs. Adult mongrel dogs of both sexes, weighing 18–24 kg, were used for auto and allo small bowel transplantation. The entire small bowels, except for short segments at the proximal and distal ends, were switched between a pair of dogs (allograft). Animals receivi...

  11. A relationship between bruxism and orofacial-dystonia? A trigeminal electrophysiological approach in a case report of pineal cavernoma

    OpenAIRE

    Frisardi, Gianni; Iani, Cesare; Sau, Gianfranco; Frisardi, Flavio; Leonardis, Carlo; Lumbau, Aurea Maria Immacolata; Enrico, Paolo; Sirca, Donatella; Staderini, Enrico Maria; Chessa, Giacomo Innocenzo

    2013-01-01

    Background: In some clinical cases, bruxism may be correlated to central nervous system hyperexcitability, suggesting that bruxism may represent a subclinical form of dystonia. To examine this hypothesis, we performed an electrophysiological evaluation of the excitability of the trigeminal nervous system in a patient affected by pineal cavernoma with pain symptoms in the orofacial region and pronounced bruxism. Methods: Electrophysiological studies included bilateral electrical transcrania...

  12. Electrophysiological characteristics of paroxysmal atrial fibrillation originating from superior vena cava: a clinical analysis of 30 cases

    OpenAIRE

    Shi, Xiang-min; YUAN, HONG-TAO; Guo, Hong-Yang; Guo, Jian-Ping; Shan, Zhao-Liang; Wang, Yu-tang

    2015-01-01

    To analyze characteristics of electrocardiogram (ECG), electrophysiological intracardiac mapping and radiofrequency ablation (RF) of paroxysmal atrial fibrillation (PAF) originating from superior vena cava (SVC), aiming to investigate electrophysiological characteristics of PAF with SVC origin. Clinical data of 30 subjects (18 men and 12 women, aged, 58.6 ± 15.5 years) with PAF of SVC origin were retrospectively analyzed; All patients underwent RF during 2006.9-2012.7. ECG of AF and atrial pr...

  13. [Out-of-hospital cardiac arrest].

    Science.gov (United States)

    Virkkunen, Ilkka; Hoppu, Sanna; Kämäräinen, Antti

    2011-01-01

    Cardiac arrest as the first symptom of coronary artery disease is not uncommon. Some of previously healthy people with sudden cardiac arrest may be saved by effective resuscitation and post-resuscitative therapy. The majority of cardiac arrest patients experience the cardiac arrest outside of the hospital, in which case early recognition of lifelessness, commencement of basic life support and entry to professional care without delay are the prerequisites for recovery. After the heart has started beating again, the clinical picture of post-resuscitation syndrome must be recognized and appropriate treatment utilized. PMID:22204143

  14. Detecting deterministic dy namics of cardiac rhythm

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Under the acceptable hypothesis that cardiac rhythm is an approximately deterministic process with a small scale noise component, an available way is provided to construct a model that can reflect its prominent dynamics of the deterministic component. When applied to the analysis of 19 heart rate data sets, three main findings are stated. The obtained model can reflect prominent dynamics of the deterministic component of cardiac rhythm; cardiac chaos is stated in a reliable way; dynamical noise plays an important role in the generation of complex cardiac rhythm.``

  15. Electrophysiological mechanisms of biased response to smoking-related cues in young smokers.

    Science.gov (United States)

    Cheng, Jiadong; Guan, Yanyan; Zhang, Yajuan; Bi, Yanzhi; Bu, Limei; Li, Yangding; Shi, Sha; Liu, Peng; Lu, Xiaoqi; Yu, Dahua; Yuan, Kai

    2016-08-26

    Cigarette smoking during young adult may result in serious health issues in later life. Hence, it is extremely necessary to study the smoking neurophysiological mechanisms in this critical transitional period. However, few studies revealed the electrophysiological mechanisms of cognitive processing biases in young adult smokers. In present study, nineteen young smokers with 12h abstinent and 19 matched nonsmokers were recruited. By employing event-related potentials (ERP) measurements during a smoking cue induced craving task, electrophysiological brain responses were compared between the young adult smokers and nonsmokers. The Slow Positive Wave (SPW) amplitude of smoking-related cues was enhanced in young adult smokers compared with nonsmokers. In addition, increased P300/SPW component of smoking-related cues relative to neutral cues were found in young adult smokers. Meanwhile, a positive correlation between Cigarette Per Day (CPD) and the amplitude of ERPs wave (P300/SPW) at anterior (Fz), central (Cz) were observed in young adult smokers. Our findings provided direct electrophysiological evidence for the cognitive processing bias of smoking cue and may shed new insights into the smoking behavior in young adult smokers. PMID:27373532

  16. Relevance of cellular to clinical electrophysiology in interpreting antiarrhythmic drug action.

    Science.gov (United States)

    Vaughan Williams, E M

    1989-12-01

    The usefulness of cellular electrophysiologic techniques in elucidating the fundamental actions of antiarrhythmic drugs is contrasted with their apparent lack of relevance to the selection of drugs for the treatment of particular arrhythmias. Clinical electrophysiologists employ different techniques, but their results may be explained in terms of cellular drug actions. The varying clinical effects of class IA, IB and IC agents are due to differences in the speed of their attachment to, and detachment from, sodium channels. The role of sympathetic activity in arrhythmogenesis is complex, but again readily explicable in terms of the electrophysiologic cellular actions of stimulation of the individual types of adrenoceptors (alpha 1, alpha 2, beta 1 and beta 2) and the distribution of these receptors, and of the longterm effects of sympathetic deprivation, either by antisympathetic drugs (class II) or by sympathetic denervation. Delayed repolarization (e.g., by class III drugs or prolonged beta blockade) is antiarrhythmic because it is homogeneous, despite the incidental prolongation of QT. If, however, QT is prolonged by heterogeneity of conduction or repolarization, or by partial sympathetic denervation (long QT syndrome or post myocardial infarction), this indicates increased risk of arrhythmia. Finally, the efficacy of calcium antagonists (class IV) in supraventricular arrhythmias is attributable to the cellular electrophysiologic characteristics of sinoatrial and atrioventricular nodal and transitional elements.

  17. Optical coherence tomography and electrophysiology of retinal and visual pathways in Wilson's disease.

    Science.gov (United States)

    Langwińska-Wośko, Ewa; Litwin, Tomasz; Szulborski, Kamil; Członkowska, Anna

    2016-04-01

    We evaluated correlations between positive findings of changes on brain magnetic resonance imaging (MRI) and selected morphological and electrophysiological parameters of the retinal and visual systems in Wilson's disease. Fifty-eight Wilson's disease symptomatic patients were divided according to whether they displayed brain changes on MRI (positive, n = 39; negative, n = 19). All participants and healthy control group (n = 30), underwent retinal optical coherence tomography to assess the thickness of macula and the total retinal nerve fiber layer. Visual evoked potentials were measured and electroretinography was performed. Macular and retinal nerve fibers were thinner in participants with changes on MRI than in participants without changes. Electrophysiological parameters were markedly different in the MRI positive group compared with the negative group and 30 healthy controls; however, some abnormalities were evident in cases without visible brain pathology. Morphological and electrophysiological changes of retinal and visual pathways are associated with MRI visualized brain injury in Wilson's disease and may be useful for detecting the degree of neurodegeneration.

  18. The sound of feelings: electrophysiological responses to emotional speech in alexithymia.

    Directory of Open Access Journals (Sweden)

    Katharina Sophia Goerlich

    Full Text Available BACKGROUND: Alexithymia is a personality trait characterized by difficulties in the cognitive processing of emotions (cognitive dimension and in the experience of emotions (affective dimension. Previous research focused mainly on visual emotional processing in the cognitive alexithymia dimension. We investigated the impact of both alexithymia dimensions on electrophysiological responses to emotional speech in 60 female subjects. METHODOLOGY: During unattended processing, subjects watched a movie while an emotional prosody oddball paradigm was presented in the background. During attended processing, subjects detected deviants in emotional prosody. The cognitive alexithymia dimension was associated with a left-hemisphere bias during early stages of unattended emotional speech processing, and with generally reduced amplitudes of the late P3 component during attended processing. In contrast, the affective dimension did not modulate unattended emotional prosody perception, but was associated with reduced P3 amplitudes during attended processing particularly to emotional prosody spoken in high intensity. CONCLUSIONS: Our results provide evidence for a dissociable impact of the two alexithymia dimensions on electrophysiological responses during the attended and unattended processing of emotional prosody. The observed electrophysiological modulations are indicative of a reduced sensitivity to the emotional qualities of speech, which may be a contributing factor to problems in interpersonal communication associated with alexithymia.

  19. Electrophysiological mechanisms of biased response to smoking-related cues in young smokers.

    Science.gov (United States)

    Cheng, Jiadong; Guan, Yanyan; Zhang, Yajuan; Bi, Yanzhi; Bu, Limei; Li, Yangding; Shi, Sha; Liu, Peng; Lu, Xiaoqi; Yu, Dahua; Yuan, Kai

    2016-08-26

    Cigarette smoking during young adult may result in serious health issues in later life. Hence, it is extremely necessary to study the smoking neurophysiological mechanisms in this critical transitional period. However, few studies revealed the electrophysiological mechanisms of cognitive processing biases in young adult smokers. In present study, nineteen young smokers with 12h abstinent and 19 matched nonsmokers were recruited. By employing event-related potentials (ERP) measurements during a smoking cue induced craving task, electrophysiological brain responses were compared between the young adult smokers and nonsmokers. The Slow Positive Wave (SPW) amplitude of smoking-related cues was enhanced in young adult smokers compared with nonsmokers. In addition, increased P300/SPW component of smoking-related cues relative to neutral cues were found in young adult smokers. Meanwhile, a positive correlation between Cigarette Per Day (CPD) and the amplitude of ERPs wave (P300/SPW) at anterior (Fz), central (Cz) were observed in young adult smokers. Our findings provided direct electrophysiological evidence for the cognitive processing bias of smoking cue and may shed new insights into the smoking behavior in young adult smokers.

  20. Large-scale electrophysiology: acquisition, compression, encryption, and storage of big data.

    Science.gov (United States)

    Brinkmann, Benjamin H; Bower, Mark R; Stengel, Keith A; Worrell, Gregory A; Stead, Matt

    2009-05-30

    The use of large-scale electrophysiology to obtain high spatiotemporal resolution brain recordings (>100 channels) capable of probing the range of neural activity from local field potential oscillations to single-neuron action potentials presents new challenges for data acquisition, storage, and analysis. Our group is currently performing continuous, long-term electrophysiological recordings in human subjects undergoing evaluation for epilepsy surgery using hybrid intracranial electrodes composed of up to 320 micro- and clinical macroelectrode arrays. DC-capable amplifiers, sampling at 32kHz per channel with 18-bits of A/D resolution are capable of resolving extracellular voltages spanning single-neuron action potentials, high frequency oscillations, and high amplitude ultra-slow activity, but this approach generates 3 terabytes of data per day (at 4 bytes per sample) using current data formats. Data compression can provide several practical benefits, but only if data can be compressed and appended to files in real-time in a format that allows random access to data segments of varying size. Here we describe a state-of-the-art, scalable, electrophysiology platform designed for acquisition, compression, encryption, and storage of large-scale data. Data are stored in a file format that incorporates lossless data compression using range-encoded differences, a 32-bit cyclically redundant checksum to ensure data integrity, and 128-bit encryption for protection of patient information.

  1. Toward a New Application of Real-Time Electrophysiology: Online Optimization of Cognitive Neurosciences Hypothesis Testing

    Directory of Open Access Journals (Sweden)

    Gaëtan Sanchez

    2014-01-01

    Full Text Available Brain-computer interfaces (BCIs mostly rely on electrophysiological brain signals. Methodological and technical progress has largely solved the challenge of processing these signals online. The main issue that remains, however, is the identification of a reliable mapping between electrophysiological measures and relevant states of mind. This is why BCIs are highly dependent upon advances in cognitive neuroscience and neuroimaging research. Recently, psychological theories became more biologically plausible, leading to more realistic generative models of psychophysiological observations. Such complex interpretations of empirical data call for efficient and robust computational approaches that can deal with statistical model comparison, such as approximate Bayesian inference schemes. Importantly, the latter enable the optimization of a model selection error rate with respect to experimental control variables, yielding maximally powerful designs. In this paper, we use a Bayesian decision theoretic approach to cast model comparison in an online adaptive design optimization procedure. We show how to maximize design efficiency for individual healthy subjects or patients. Using simulated data, we demonstrate the face- and construct-validity of this approach and illustrate its extension to electrophysiology and multiple hypothesis testing based on recent psychophysiological models of perception. Finally, we discuss its implications for basic neuroscience and BCI itself.

  2. 3D stereotaxis for epileptic foci through integrating MR imaging with neurological electrophysiology data

    International Nuclear Information System (INIS)

    Objective: To improve the accuracy of the epilepsy diagnoses by integrating MR image from PACS with data from neurological electrophysiology. The integration is also very important for transmiting diagnostic information to 3D TPS of radiotherapy. Methods: The electroencephalogram was redisplayed by EEG workstation, while MR image was reconstructed by Brainvoyager software. 3D model of patient brain was built up by combining reconstructed images with electroencephalogram data in Base 2000. 30 epileptic patients (18 males and 12 females) with their age ranged from 12 to 54 years were confirmed by using the integrated MR images and the data from neurological electrophysiology and their 3D stereolocating. Results: The corresponding data in 3D model could show the real situation of patients' brain and visually locate the precise position of the focus. The suddessful rate of 3D guided operation was greatly improved, and the number of epileptic onset was markedly decreased. The epilepsy was stopped for 6 months in 8 of the 30 patients. Conclusion: The integration of MR image and information of neurological electrophysiology can improve the diagnostic level for epilepsy, and it is crucial for imp roving the successful rate of manipulations and the epilepsy analysis. (authors)

  3. GIRK channel activation via adenosine or muscarinic receptors has similar effects on rat atrial electrophysiology.

    Science.gov (United States)

    Wang, Xiaodong; Liang, Bo; Skibsbye, Lasse; Olesen, Søren-Peter; Grunnet, Morten; Jespersen, Thomas

    2013-08-01

    G protein-coupled inwardly rectifying K⁺ channels (GIRK) are important in the regulation of heart rate and atrial electrophysiology. GIRK channels are activated by G protein-coupled receptors, including muscarinic M₂ receptors and adenosine A₁ receptors. The aim of this study was to characterize and compare the electrophysiological effects of acetylcholine (ACh) and adenosine on GIRK channels in rat atria. Action potential duration at 90% repolarization (APD₉₀), effective refractory period (ERP), and resting membrane potential (RMP) were investigated in isolated rat atria by intracellular recordings. Both the adenosine analog N6-cyclopentyladenosine (CPA) and ACh profoundly shortened APD₉₀ and ERP and hyperpolarized the RMP. No additive or synergistic effect of CPA and ACh coapplication was observed. To antagonize GIRK channel activation, the specific inhibitor rTertiapin Q (TTQ) was applied. The coapplication of TTQ reversed the CPA and ACh-induced effects. When TTQ was applied without exogenous receptor activator, both APD₉₀ and ERP were prolonged and RMP was depolarized, confirming a basal activity of the GIRK current. The results reveal that activation of A₁ and M₂ receptors has a profound and equal effect on the electrophysiology in rat atrium. This effect is to a major extent mediated through GIRK channels. Furthermore, these results support the notion that atrial GIRK currents from healthy hearts have a basal component and additional activation can be mediated via at least 2 different receptor mechanisms. PMID:23609329

  4. An electrophysiological dissociation between orbitofrontal reality filtering and context source monitoring.

    Science.gov (United States)

    Bouzerda-Wahlen, Aurélie; Nahum, Louis; Liverani, Maria Chiara; Guggisberg, Adrian G; Schnider, Armin

    2015-01-01

    Memory influences behavior in multiple ways. One important aspect is to remember in what precise context in the past a piece of information was acquired (context source monitoring). Another important aspect is to sense whether an upcoming thought, composed of fragments of memories, refers to present reality and can be acted upon (orbitofrontal reality filtering). Whether these memory control processes share common underlying mechanisms is unknown. Failures of both have been held accountable for false memories, including confabulation. Electrophysiological and imaging studies suggest a dissociation but used very different paradigms. In this study, we juxtaposed the requirements of context source monitoring and reality filtering within a unique continuous recognition task, which healthy participants performed while high-resolution evoked potentials were recorded. The mechanisms dissociated both behaviorally and electrophysiologically: Reality filtering induced a frontal positivity, absence of a specific electrocortical configuration, and posterior medial orbitofrontal activity at 200-300 msec. Context source monitoring had no electrophysiological expression in this early period. It was slower and less accurate than reality filtering and induced a prolonged positive potential over frontal leads starting at 400 msec. The study demonstrates a hitherto unrecognized separation between orbitofrontal reality filtering and source monitoring. Whereas deficient orbitofrontal reality filtering is associated with reality confusion in thinking, the behavioral correlates of deficient source monitoring should be verified with controlled experimental exploration. PMID:25061928

  5. Coupled electrophysiological recording and single cell transcriptome analyses revealed molecular mechanisms underlying neuronal maturation.

    Science.gov (United States)

    Chen, Xiaoying; Zhang, Kunshan; Zhou, Liqiang; Gao, Xinpei; Wang, Junbang; Yao, Yinan; He, Fei; Luo, Yuping; Yu, Yongchun; Li, Siguang; Cheng, Liming; Sun, Yi E

    2016-03-01

    The mammalian brain is heterogeneous, containing billions of neurons and trillions of synapses forming various neural circuitries, through which sense, movement, thought, and emotion arise. The cellular heterogeneity of the brain has made it difficult to study the molecular logic of neural circuitry wiring, pruning, activation, and plasticity, until recently, transcriptome analyses with single cell resolution makes decoding of gene regulatory networks underlying aforementioned circuitry properties possible. Here we report success in performing both electrophysiological and whole-genome transcriptome analyses on single human neurons in culture. Using Weighted Gene Coexpression Network Analyses (WGCNA), we identified gene clusters highly correlated with neuronal maturation judged by electrophysiological characteristics. A tight link between neuronal maturation and genes involved in ubiquitination and mitochondrial function was revealed. Moreover, we identified a list of candidate genes, which could potentially serve as biomarkers for neuronal maturation. Coupled electrophysiological recording and single cell transcriptome analysis will serve as powerful tools in the future to unveil molecular logics for neural circuitry functions. PMID:26883038

  6. The virtual intestine: in silico modeling of small intestinal electrophysiology and motility and the applications.

    Science.gov (United States)

    Du, Peng; Paskaranandavadivel, Niranchan; Angeli, Timothy R; Cheng, Leo K; O'Grady, Gregory

    2016-01-01

    The intestine comprises a long hollow muscular tube organized in anatomically and functionally discrete compartments, which digest and absorb nutrients and water from ingested food. The intestine also plays key roles in the elimination of waste and protection from infection. Critical to all of these functions is the intricate, highly coordinated motion of the intestinal tract, known as motility, which is coregulated by hormonal, neural, electrophysiological and other factors. The Virtual Intestine encapsulates a series of mathematical models of intestinal function in health and disease, with a current focus on motility, and particularly electrophysiology. The Virtual Intestine is being cohesively established across multiple physiological scales, from sub/cellular functions to whole organ levels, facilitating quantitative evaluations that present an integrative in silico framework. The models are also now finding broad physiological applications, including in evaluating hypotheses of slow wave pacemaker mechanisms, smooth muscle electrophysiology, structure-function relationships, and electromechanical coupling. Clinical applications are also beginning to follow, including in the pathophysiology of motility disorders, diagnosing intestinal ischemia, and visualizing colonic dysfunction. These advances illustrate the emerging potential of the Virtual Intestine to effectively address multiscale research challenges in interdisciplinary gastrointestinal sciences.

  7. 42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.

    Science.gov (United States)

    2010-10-01

    ... and intensive cardiac rehabilitation program: Conditions of coverage. (a) Definitions. As used in this... 42 Public Health 2 2010-10-01 2010-10-01 false Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage. 410.49 Section 410.49 Public Health CENTERS...

  8. Tumors of the cardiac conduction system: are they an explanation for otherwise unexplained sudden cardiac death?

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Cardiac tumors are well described in the literature. The first reports of cardiac tumors date back hundreds of years.The prevalence of primary cardiac tumors at autopsy ranges from 0.001% to 0.3% with secondary tumors more common than in primary tumors.

  9. Electrical wave propagation in an anisotropic model of the left ventricle based on analytical description of cardiac architecture.

    Directory of Open Access Journals (Sweden)

    Sergey F Pravdin

    Full Text Available We develop a numerical approach based on our recent analytical model of fiber structure in the left ventricle of the human heart. A special curvilinear coordinate system is proposed to analytically include realistic ventricular shape and myofiber directions. With this anatomical model, electrophysiological simulations can be performed on a rectangular coordinate grid. We apply our method to study the effect of fiber rotation and electrical anisotropy of cardiac tissue (i.e., the ratio of the conductivity coefficients along and across the myocardial fibers on wave propagation using the ten Tusscher-Panfilov (2006 ionic model for human ventricular cells. We show that fiber rotation increases the speed of cardiac activation and attenuates the effects of anisotropy. Our results show that the fiber rotation in the heart is an important factor underlying cardiac excitation. We also study scroll wave dynamics in our model and show the drift of a scroll wave filament whose velocity depends non-monotonically on the fiber rotation angle; the period of scroll wave rotation decreases with an increase of the fiber rotation angle; an increase in anisotropy may cause the breakup of a scroll wave, similar to the mother rotor mechanism of ventricular fibrillation.

  10. ECLS in Pediatric Cardiac Patients

    Science.gov (United States)

    Di Nardo, Matteo; MacLaren, Graeme; Marano, Marco; Cecchetti, Corrado; Bernaschi, Paola; Amodeo, Antonio

    2016-01-01

    Extracorporeal life support (ECLS) is an important device in the management of children with severe refractory cardiac and or pulmonary failure. Actually, two forms of ECLS are available for neonates and children: extracorporeal membrane oxygenation (ECMO) and use of a ventricular assist device (VAD). Both these techniques have their own advantages and disadvantages. The intra-aortic balloon pump is another ECLS device that has been successfully used in larger children, adolescents, and adults, but has found limited applicability in smaller children. In this review, we will present the “state of art” of ECMO in neonate and children with heart failure. ECMO is commonly used in a variety of settings to provide support to critically ill patients with cardiac disease. However, a strict selection of patients and timing of intervention should be performed to avoid the increase in mortality and morbidity of these patients. Therefore, every attempt should be done to start ECLS “urgently” rather than “emergently,” before the presence of dysfunction of end organs or circulatory collapse. Even though exciting progress is being made in the development of VADs for long-term mechanical support in children, ECMO remains the mainstay of mechanical circulatory support in children with complex anatomy, particularly those needing rapid resuscitation and those with a functionally univentricular circulation. With the increase in familiarity with ECMO, new indications have been added, such as extracorporeal cardiopulmonary resuscitation (ECPR). The literature supporting ECPR is increasing in children. Reasonable survival rates have been achieved after initiation of support during active compressions of the chest following in-hospital cardiac arrest. Contraindications to ECLS have reduced in the last 5 years and many centers support patients with functionally univentricular circulations. Improved results have been recently achieved in this complex subset of patients. PMID

  11. EVALUATION OF NEONATAL CARDIAC MURMURS

    Directory of Open Access Journals (Sweden)

    Somaiah

    2014-09-01

    Full Text Available Cardiovascular malformations are the most common cause of congenital malformations, the diagnosis of which requires a close observation in the neonatal period. Early recognition of CHD is important in the neonatal period, as many of them may be fatal if undiagnosed and may require immediate intervention. The objectives of this study are to study the epidemiology of neonatal cardiac murmurs, to identify clinical characteristics which differentiate pathological murmur from functional murmurs and to assess the reliability of clinical evaluation in diagnosing CHD. Method of study included all neonates admitted to the NICU, postnatal ward, attending pediatric OPD or neonatal follow up clinic and were detected to have cardiac murmurs. It was a cross sectional study over a period of 16months. A clinical diagnosis was made based on history and clinical examination. Then Chest X-ray and ECG, Echocardiography was done in all neonates for confirmation of the diagnosis. These neonates were again examined daily till they were in hospital and during the follow-up visit at 6 weeks. The results of 70 neonates in this study conducted over a period of 24 months included the incidence of cardiac murmurs among intramural neonates which was 13.5 for 1000 live births. Most frequent symptom was fast breathing in 10(14.3% cases. VSD was the most common diagnosis clinically in 23 (33% babies. The most frequent Echo diagnosis was acyanotic complex congenital heart disease in 25(36% cases followed by 12(17% cases each of VSD and ASD respectively. Overall in our study 77.1% (54cases of the murmurs were diagnosed correctly and confirmed by Echocardiography The study concluded that it is possible to make clinical diagnosis in many cases of congenital heart diseases, the functional murmurs could be differentiated from those arising from structural heart disease and evaluation of the infants based only on murmurs, few congenital heart diseases can be missed.

  12. A statistical method for retrospective cardiac and respiratory motion gating of interventional cardiac x-ray images

    Energy Technology Data Exchange (ETDEWEB)

    Panayiotou, Maria, E-mail: maria.panayiotou@kcl.ac.uk; King, Andrew P.; Housden, R. James; Ma, YingLiang; Rhode, Kawal S. [Division of Imaging Sciences and Biomedical Engineering, King' s College London, London SE1 7EH (United Kingdom); Cooklin, Michael; O' Neill, Mark; Gill, Jaswinder; Rinaldi, C. Aldo [Department of Cardiology, Guy' s and St. Thomas' Hospitals NHS Foundation Trust, London SE1 7EH (United Kingdom)

    2014-07-15

    Purpose: Image-guided cardiac interventions involve the use of fluoroscopic images to guide the insertion and movement of interventional devices. Cardiorespiratory gating can be useful for 3D reconstruction from multiple x-ray views and for reducing misalignments between 3D anatomical models overlaid onto fluoroscopy. Methods: The authors propose a novel and potentially clinically useful retrospective cardiorespiratory gating technique. The principal component analysis (PCA) statistical method is used in combination with other image processing operations to make our proposed masked-PCA technique suitable for cardiorespiratory gating. Unlike many previously proposed techniques, our technique is robust to varying image-content, thus it does not require specific catheters or any other optically opaque structures to be visible. Therefore, it works without any knowledge of catheter geometry. The authors demonstrate the application of our technique for the purposes of retrospective cardiorespiratory gating of normal and very low dose x-ray fluoroscopy images. Results: For normal dose x-ray images, the algorithm was validated using 28 clinical electrophysiology x-ray fluoroscopy sequences (2168 frames), from patients who underwent radiofrequency ablation (RFA) procedures for the treatment of atrial fibrillation and cardiac resynchronization therapy procedures for heart failure. The authors established end-systole, end-expiration, and end-inspiration success rates of 97.0%, 97.9%, and 97.0%, respectively. For very low dose applications, the technique was tested on ten x-ray sequences from the RFA procedures with added noise at signal to noise ratio (SNR) values of√(5)0, √(1)0, √(8), √(6), √(5), √(2), and √(1) to simulate the image quality of increasingly lower dose x-ray images. Even at the low SNR value of √(2), representing a dose reduction of more than 25 times, gating success rates of 89.1%, 88.8%, and 86.8% were established. Conclusions: The proposed

  13. A statistical method for retrospective cardiac and respiratory motion gating of interventional cardiac x-ray images

    International Nuclear Information System (INIS)

    Purpose: Image-guided cardiac interventions involve the use of fluoroscopic images to guide the insertion and movement of interventional devices. Cardiorespiratory gating can be useful for 3D reconstruction from multiple x-ray views and for reducing misalignments between 3D anatomical models overlaid onto fluoroscopy. Methods: The authors propose a novel and potentially clinically useful retrospective cardiorespiratory gating technique. The principal component analysis (PCA) statistical method is used in combination with other image processing operations to make our proposed masked-PCA technique suitable for cardiorespiratory gating. Unlike many previously proposed techniques, our technique is robust to varying image-content, thus it does not require specific catheters or any other optically opaque structures to be visible. Therefore, it works without any knowledge of catheter geometry. The authors demonstrate the application of our technique for the purposes of retrospective cardiorespiratory gating of normal and very low dose x-ray fluoroscopy images. Results: For normal dose x-ray images, the algorithm was validated using 28 clinical electrophysiology x-ray fluoroscopy sequences (2168 frames), from patients who underwent radiofrequency ablation (RFA) procedures for the treatment of atrial fibrillation and cardiac resynchronization therapy procedures for heart failure. The authors established end-systole, end-expiration, and end-inspiration success rates of 97.0%, 97.9%, and 97.0%, respectively. For very low dose applications, the technique was tested on ten x-ray sequences from the RFA procedures with added noise at signal to noise ratio (SNR) values of√(5)0, √(1)0, √(8), √(6), √(5), √(2), and √(1) to simulate the image quality of increasingly lower dose x-ray images. Even at the low SNR value of √(2), representing a dose reduction of more than 25 times, gating success rates of 89.1%, 88.8%, and 86.8% were established. Conclusions: The proposed

  14. Cerebral oximetry in cardiac anesthesia

    Science.gov (United States)

    Vretzakis, George; Georgopoulou, Stauroula; Stamoulis, Konstantinos; Stamatiou, Georgia; Tsakiridis, Kosmas; Katsikogianis, Nikolaos; Kougioumtzi, Ioanna; Machairiotis, Nikolaos; Tsiouda, Theodora; Mpakas, Andreas; Beleveslis, Thomas; Koletas, Alexander; Siminelakis, Stavros N.; Zarogoulidis, Konstantinos

    2014-01-01

    Cerebral oximetry based on near-infrared spectroscopy (NIRS) is increasingly used during the perioperative period of cardiovascular operations. It is a noninvasive technology that can monitor the regional oxygen saturation of the frontal cortex. Current literature indicates that it can stratify patients preoperatively according their risk. Intraoperatively, it provides continuous information about brain oxygenation and allows the use of brain as sentinel organ indexing overall organ perfusion and injury. This review focuses on the clinical validity and applicability of this monitor for cardiac surgical patients. PMID:24672700

  15. Cardiac leiomyosarcoma, a case report

    DEFF Research Database (Denmark)

    Andersen, Rikke; Kristensen, Bjarne W; Gill, Sabine

    2013-01-01

    In this case report we present the history of a patient admitted with recurrent pulmonary edema. Transesophageal chocardiography showed a tumour in the left atrium, occluding the ostium of the mitral valve and mimicking intermittent mitral stenosis. Cardiac surgery followed by pathological...... examination revealed that the tumour was a leiomyosarcoma. Images from the echocardiography as well as the pathological findings are shown and discussed. The present case report illustrates that atrial tumors comprise also sarcomas, suggesting the use of careful, rapid diagnostic procedures and treatment...

  16. Cardiac imaging: does radiation matter?

    Science.gov (United States)

    Einstein, Andrew J.; Knuuti, Juhani

    2012-01-01

    The use of ionizing radiation in cardiovascular imaging has generated considerable discussion. Radiation should not be considered in isolation, but rather in the context of a careful examination of the benefits, risks, and costs of cardiovascular imaging. Such consideration requires an understanding of some fundamental aspects of the biology, physics, epidemiology, and terminology germane to radiation, as well as principles of radiological protection. This paper offers a concise, contemporary perspective on these areas by addressing pertinent questions relating to radiation and its application to cardiac imaging. PMID:21828062

  17. Autologous Transfusion in Cardiac Surgery

    Directory of Open Access Journals (Sweden)

    Radmehr H

    2003-11-01

    Full Text Available Preoperative autologous blood donation is commonly used to reduce exposure to homologous blood transfusions among patients undergoing elective cardiac surgery. The aim of this study was to evaluate the effect of autologous transfusion on patients' hematocryte value, intra and postoperative blood loss, hospitalization time, the development of infective complications and other factors. Materials and Methods: Between June 2001 to April 2002, 208 patients were underwent cardiac surgery in cardiac surgery ward in Imam Khomeini Medical Center. One or more blood units donate from 104 Patients before cardiopulmonary bypass and heparin injection, and transfused to them after CPB and Protamin injection (autologous Group, group 1. 104 patients underwent cardiac surgery routinely (control group, group 2."nResults: Mean of age was 55.9±8.6 in group 1 and 56.6±9.3 in group 2 (P=NS. 73 male and 31 females were in group 1 and 79 males and 25 females were in group 2 (P=NS. Smoking, familial history, hyperlipidemia, diabetes mellitus, renal failure, hypertension, stroke, and history of myocardial infarction was similar in two groups."nSeverity of angina, urgency operation, number vessels disease, duration of cardiopulmonary bypass, duration of aortic cross clamp time, use of internal thoracic artery graft, and number of grafts was similar in both groups. Mean of bleeding post operation was 548 cc in group 1 and 803 cc in-group 2 (P=0.003. Bleeding that need to operation was 1.8% in group 1 and 8.6% in group 2 (P=0.002. Wound infection, mediastinitis, renal failure, ventilatory prolonged, stroke, need to Intra-aortic Balloon Pump (IABP, intraoperative bleeding, and hospital stay was similar in both groups. Mean of extubationt time was 10.2 hours in group 1 and 14.8 hours in group 2 (P=0.001."nConclusion: Preoperative and intra-operative donations are safe and continue to contribute uniquely to blood conservation, providing important options in comprehensive

  18. [Acute cardiac failure in pheochromocytoma.

    DEFF Research Database (Denmark)

    Jønler, Morten; Munk, Kim

    2008-01-01

    Pheochromocytoma (P) is an endocrine catecholamine-secreting tumor. Classical symptoms like hypertension, attacks of sweating, palpitations, headache and palor are related to catecholamine discharge. We provide a case of P in a 71 year-old man presenting with acute cardiac failure, severe reduction...... in left ventricular function and elevated myocardial enzymes. No coronary stenoses were found. The myocardium regained nearly normal systolic function in one and a half month. A renal P was laparoscopicaly removed. We discuss the pathophysiology of catecholamine cardiomyopathy. Udgivelsesdato: 2008-Jun-2...

  19. Assessment of cardiac sympathetic nerve integrity with positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Raffel, David M. E-mail: raffel@umich.edu; Wieland, Donald M

    2001-07-01

    The autonomic nervous system plays a critical role in the regulation of cardiac function. Abnormalities of cardiac innervation have been implicated in the pathophysiology of many heart diseases, including sudden cardiac death and congestive heart failure. In an effort to provide clinicians with the ability to regionally map cardiac innervation, several radiotracers for imaging cardiac sympathetic neurons have been developed. This paper reviews the development of neuronal imaging agents and discusses their emerging role in the noninvasive assessment of cardiac sympathetic innervation.

  20. The Cardiac Conduction System: Generation and Conduction of the Cardiac Impulse.

    Science.gov (United States)

    Kennedy, Alan; Finlay, Dewar D; Guldenring, Daniel; Bond, Raymond; Moran, Kieran; McLaughlin, James

    2016-09-01

    In this article, the authors outline the key components behind the automated generation of the cardiac impulses and the effect these impulses have on cardiac myocytes. Also, a description of the key components of the normal cardiac conduction system is provided, including the sinoatrial node, the atrioventricular node, the His bundle, the bundle branches, and the Purkinje network. Finally, an outline of how each stage of the cardiac conduction system is represented on the electrocardiogram is described, allowing the reader of the electrocardiogram to translate background information about the normal cardiac conduction system to everyday clinical practice. PMID:27484656