The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Simulation of cardiac excitation is often a trade-off between accuracy and speed. A promising minimal, time-efficient cell model with four state variables has recently been presented together with parametrizations for ventricular cell behaviour. In this work, we adapt the model parameters to reproduce atrial excitation properties as given by the Courtemanche model. The action potential shape is considered...
Increasing biophysical detail in multi physical, multiscale cardiac model will demand higher levels of parallelism in multi-core approaches to obtain fast simulation times. As an example of such a highly parallel multi-core approaches, we develop a completely distributed bidomain cardiac model implemented on the IBM Blue Gene/L architecture. A tissue block of size 50 times 50 times 100 cubic elements...
The sinus node is the primary pacemaker of the heart. A complex interplay of heterogeneities is assumed to be the basic mechanism that the sinus node can drive the heart. This interplay can be disturbed by e.g. diseases, drugs or mutations. In this work the effect of a mutation on the sinus node function were investigated. Therefore, measurement data of wild-type and mutant IKr channels were integrated...
Heterogeneity of ion channel properties within human ventricular tissue determines the sequence of repolarization under healthy conditions. In this computational study, the impact of different extend of electrophysiological heterogeneity in both human ventricles on the ECG was investigated by a forward calculation of the cardiac electrical signals on the body surface. The gradients ranged from solely...
The term cardiac mechano- electrical feedback precis the various phenomena related to modulation of electrophysiology by mechanical deformation of cells and tissues of the heart. The significance of mechano-electrical feedback and the underlying mechanisms are still poorly understood despite intense experimental research. We introduce and discuss a framework for computational modeling and simulation...
The congenital long-QT syndrome is commonly associated with a high risk for polymorphic ventricular tachycardia and sudden cardiac death. This is probably due to an intensification of the intrinsic heterogeneities present in ventricular myocardium. Increasing the electrophysiological heterogeneities amplifies the dispersion of repolarization which directly affects the morphology of the T wave in the...
Accurate numerical simulations of the electrical and mechanical activities of the heart require suitable anatomical models including muscle fiber orientation. In this work, a model based on diffusion tensor imaging delivering both geometrical information and fiber orientation was developed. The dataset was segmented into a variety of tissue classes including fiber orientation information in the two...
Genetically engineered cardiac pacemakers are a proposed alternative or support to the state-of-the-art electronic devices. Down-regulation of the expression of Kir2.1 channels reduces the activity of the inward rectifier current IK1 and turns ventricular cardiomyocytes to pacemaker cells. This effect was mimicked in computational cells describing heterogeneous human ventricular electrophysiology...
Atrial fibrillation (AF) induces variations in channel characteristics of human atrial myocytes. Data from experimental AF studies was incorporated in a computational model It was used to investigate the effects of electrophysiological remodeling on myocardial behavior This model was integrated in a schematic 2D model of human right atrium including the sinoatrial node, crista terminalis, pectinate...
This computational study investigates the effects of epicardial stimulation on healthy and mutant excitable tissue. A heterogeneous wild-type (WT) model of human ventricular electrophysiology and a modified version simulating short QT (SQT) syndrome were used. The utilized anisotropic anatomical structures were both a slice cut out of a human left ventricular geometry and a beam from endocardium to...
Summary form only given, as follows. A one-dimensional, Lagrangian magnetohydrodynamic (MHD) code (RAVEN) has been run in parallel with itself to model a coaxial flux-compression generator (FCG). The FCG, which is two-dimensional in character, was modeled by taking slices perpendicular to the axis. The slices were calculated simultaneously as separate, one-dimensional MHD modules which were coupled...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.