scholarly journals Period of Arrhythmia Anchored around an Infarction Scar in an Anatomical Model of the Human Ventricles

Mathematics ◽  
2021 ◽  
Vol 9 (22) ◽  
pp. 2911
Author(s):  
Daria Mangileva ◽  
Pavel Konovalov ◽  
Arsenii Dokuchaev ◽  
Olga Solovyova ◽  
Alexander V. Panfilov
Keyword(s):  
Cardiac Tissue ◽  
Rotation Period ◽  
In Silico Analysis ◽  
Generic Model ◽  
Gray Zone ◽  
Ionic Model ◽  
Anatomical Model ◽  
Ventricular Cells ◽  
Realistic Description ◽  
The Waves

Rotating nonlinear waves of excitation in the heart cause dangerous cardiac arrhythmias. Frequently, ventricular arrhythmias occur as a result of myocardial infarction and are associated with rotation of the waves around a post-infarction scar. In this paper, we perform a detailed in silico analysis of scroll waves in an anatomical model of the human ventricles with a generic model of the infarction scar surrounded by the gray zone with modified properties of the myocardial tissue. Our model includes a realistic description of the heart shape, anisotropy of cardiac tissue and a detailed description of the electrical activity in human ventricular cells by a TP06 ionic model. We vary the size of the scar and gray zone and analyze the dependence of the rotation period on the injury dimensions. Two main regimes of wave scrolling are observed: the scar rotation, when the wave rotates around the scar, and the gray zone rotation, when the wave rotates around the boundary of the gray zone and normal tissue. The transition from the gray zone to the scar rotation occurs for the width of gray zone above 10–20 mm, depending on the perimeter of the scar. We compare our results with simulations in 2D and show that 3D anisotropy reduces the period of rotation. We finally use a model with a realistic shape of the scar and show that our approach predicts correctly the period of the arrhythmia.

Small size ionic heterogeneities in the human heart can attract rotors

2014 ◽  
Vol 307 (10) ◽  
pp. H1456-H1468 ◽  
Author(s):  
Arne Defauw ◽  
Nele Vandersickel ◽  
Peter Dawyndt ◽  
Alexander V. Panfilov
Keyword(s):  
Cardiac Arrhythmias ◽  
In Silico ◽  
Human Heart ◽  
Cardiac Tissue ◽  
Two Dimensional ◽  
Anatomical Model ◽  
Practical Applications ◽  
Ventricular Cells ◽  
Local Properties ◽  
Substantial Distance

Rotors occurring in the heart underlie the mechanisms of cardiac arrhythmias. Answering the question whether or not the location of rotors is related to local properties of cardiac tissue has important practical applications. This is because ablation of rotors has been shown to be an effective way to fight cardiac arrhythmias. In this study, we investigate, in silico, the dynamics of rotors in two-dimensional and in an anatomical model of human ventricles using a Ten Tusscher-Noble-Noble-Panfilov (TNNP) model for ventricular cells. We study the effect of small size ionic heterogeneities, similar to those measured experimentally. It is shown that such heterogeneities cannot only anchor, but can also attract, rotors rotating at a substantial distance from the heterogeneity. This attraction distance depends on the extent of the heterogeneities and can be as large as 5–6 cm in realistic conditions. We conclude that small size ionic heterogeneities can be preferred localization points for rotors and discuss their possible mechanism and value for applications.

scholarly journals Rotational Activity around an Obstacle in 2D Cardiac Tissue in Presence of Cellular Heterogeneity

Mathematics ◽  
2021 ◽  
Vol 9 (23) ◽  
pp. 3090
Author(s):  
Pavel Konovalov ◽  
Daria Mangileva ◽  
Arsenii Dokuchaev ◽  
Olga Solovyova ◽  
Alexander V. Panfilov
Keyword(s):  
Cardiac Tissue ◽  
Numerical Study ◽  
Cellular Heterogeneity ◽  
Gray Zone ◽  
Electrical Excitation ◽  
Minimal Period ◽  
Ionic Model ◽  
Human Cardiomyocytes ◽  
Wave Rotation ◽  
Dynamical Instabilities

Waves of electrical excitation rotating around an obstacle is one of the important mechanisms of dangerous cardiac arrhythmias occurring in the heart damaged by a post-infarction scar. Such a scar is also surrounded by the region of heterogeneity called a gray zone. In this paper, we perform the first comprehensive numerical study of various regimes of wave rotation around an obstacle surrounded by a gray zone. We use the TP06 cellular ionic model for human cardiomyocytes and study how the period and the pattern of wave rotation depend on the radius of a circular obstacle and the width of a circular gray zone. Our main conclusions are the following. The wave rotation regimes can be subdivided into three main classes: (1) functional rotation, (2) scar rotation and the newly found (3) gray zone rotation regimes. In the scar rotation regime, the wave rotates around the obstacle, while in the gray zone regime, the wave rotates around the gray zone. As a result, the period of rotation is determined by the perimeter of the scar, or gray zone perimeter correspondingly. The transition from the scar to the gray rotation regimes can be determined from the minimal period principle, formulated in this paper. We have also observed additional regimes associated with two types of dynamical instabilities which may affect or not affect the period of rotation. The results of this study can help to identify the factors determining the period of arrhythmias in post-infarction patients.

scholarly journals Optimisation of a Generic Ionic Model of Cardiac Myocyte Electrical Activity

2013 ◽  
Vol 2013 ◽  
pp. 1-20 ◽  
Author(s):  
Tianruo Guo ◽  
Amr Al Abed ◽  
Nigel H. Lovell ◽  
Socrates Dokos
Keyword(s):  
Action Potential ◽  
Time Course ◽  
Cardiac Myocyte ◽  
Cardiac Tissue ◽  
Ionic Currents ◽  
Experimental Information ◽  
Electrical Stimulus ◽  
Right Atrial ◽  
Ionic Model ◽  
Multiple Datasets

A generic cardiomyocyte ionic model, whose complexity lies between a simple phenomenological formulation and a biophysically detailed ionic membrane current description, is presented. The model provides a user-defined number of ionic currents, employing two-gate Hodgkin-Huxley type kinetics. Its generic nature allows accurate reconstruction of action potential waveforms recorded experimentally from a range of cardiac myocytes. Using a multiobjective optimisation approach, the generic ionic model was optimised to accurately reproduce multiple action potential waveforms recorded from central and peripheral sinoatrial nodes and right atrial and left atrial myocytes from rabbit cardiac tissue preparations, under different electrical stimulus protocols and pharmacological conditions. When fitted simultaneously to multiple datasets, the time course of several physiologically realistic ionic currents could be reconstructed. Model behaviours tend to be well identified when extra experimental information is incorporated into the optimisation.

A computationally efficient electrophysiological model of human ventricular cells

2002 ◽  
Vol 282 (6) ◽  
pp. H2296-H2308 ◽  
Author(s):  
O. Bernus ◽  
R. Wilders ◽  
C. W. Zemlin ◽  
H. Verschelde ◽  
A. V. Panfilov
Keyword(s):  
Action Potential ◽  
Cardiac Tissue ◽  
Spiral Wave ◽  
Ionic Currents ◽  
Average Frequency ◽  
Computationally Efficient ◽  
Variable Model ◽  
Potential Shape ◽  
Ventricular Cells ◽  
Ventricular Tissue

Recent experimental and theoretical results have stressed the importance of modeling studies of reentrant arrhythmias in cardiac tissue and at the whole heart level. We introduce a six-variable model obtained by a reformulation of the Priebe-Beuckelmann model of a single human ventricular cell. The reformulated model is 4.9 times faster for numerical computations and it is more stable than the original model. It retains the action potential shape at various frequencies, restitution of action potential duration, and restitution of conduction velocity. We were able to reproduce the main properties of epicardial, endocardial, and M cells by modifying selected ionic currents. We performed a simulation study of spiral wave behavior in a two-dimensional sheet of human ventricular tissue and showed that spiral waves have a frequency of 3.3 Hz and a linear core of ∼50-mm diameter that rotates with an average frequency of 0.62 rad/s. Simulation results agreed with experimental data. In conclusion, the proposed model is suitable for efficient and accurate studies of reentrant phenomena in human ventricular tissue.

Transient outward current contributes to Wenckebach-like rhythms in isolated rabbit ventricular cells

1997 ◽  
Vol 273 (1) ◽  
pp. H1-H11 ◽  
Author(s):  
A. R. Yehia ◽  
A. Shrier ◽  
K. C. Lo ◽  
M. R. Guevara
Keyword(s):  
Action Potential ◽  
Potassium Current ◽  
Phase 1 ◽  
Outward Current ◽  
Transient Outward Current ◽  
Ionic Model ◽  
Recovery Interval ◽  
Ventricular Cells ◽  
Outward Potassium Current ◽  
Phase Phase

Wenckebach-like rhythms in isolated rabbit ventricular cells are characterized by beat-to-beat increments in action potential duration (APD) and latency, giving rise to a beat-to-beat decrease in the recovery interval and culminating in a skipped beat. These systematic APD changes are associated with a beat-to-beat decrease in the slope of the early repolarizing phase (phase 1) of the action potential, which is partially controlled by the transient outward potassium current (Ito). When Ito is blocked with 4-aminopyridine, periodic Wenckebach rhythms are replaced by aperiodic Wenckebach rhythms, in which the beat-to-beat changes in the slope of phase 1 and in APD disappear but the beat-to-beat increase in latency remains. A beat-to-beat decrease in Ito, paralleling the beat-to-beat changes in the slope of phase 1 and in APD, is seen in action-potential clamp experiments with Wenckebach rhythms previously recorded in the same cell. Simulations with an ionic model of Ito show cyclical changes in Ito consistent with the experimental data. These results demonstrate a key role for Ito in the generation of maintained periodic Wenckebach rhythms in isolated rabbit ventricular cells.

scholarly journals Antenatal architecture and activity of the human heart

2013 ◽  
Vol 3 (2) ◽  
pp. 20120065 ◽  
Author(s):  
Eleftheria Pervolaraki ◽  
Richard A. Anderson ◽  
Alan P. Benson ◽  
Barrie Hayes-Gill ◽  
Arun V. Holden ◽  
...  
Keyword(s):  
Computational Models ◽  
Cardiac Tissue ◽  
Molecular Mapping ◽  
Diffusion Tensor ◽  
Foetal Heart ◽  
Qt Intervals ◽  
Ventricular Cells ◽  
Adult Cell ◽  
Cardiac Geometry ◽  
Human Foetal Heart

We construct the components for a family of computational models of the electrophysiology of the human foetal heart from 60 days gestational age (DGA) to full term. This requires both cell excitation models that reconstruct the myocyte action potentials, and datasets of cardiac geometry and architecture. Fast low-angle shot and diffusion tensor magnetic resonance imaging (DT-MRI) of foetal hearts provides cardiac geometry with voxel resolution of approximately 100 μm. DT-MRI measures the relative diffusion of protons and provides a measure of the average intravoxel myocyte orientation, and the orientation of any higher order orthotropic organization of the tissue. Such orthotropic organization in the adult mammalian heart has been identified with myocardial sheets and cleavage planes between them. During gestation, the architecture of the human ventricular wall changes from being irregular and isotropic at 100 DGA to an anisotropic and orthotropic architecture by 140 DGA, when it has the smooth, approximately 120° transmural change in myocyte orientation that is characteristic of the adult mammalian ventricle. The DT obtained from DT-MRI provides the conductivity tensor that determines the spread of potential within computational models of cardiac tissue electrophysiology. The foetal electrocardiogram (fECG) can be recorded from approximately 60 DGA, and RR, PR and QT intervals between the P, R, Q and T waves of the fECG can be extracted by averaging from approximately 90 DGA. The RR intervals provide a measure of the pacemaker rate, the QT intervals an index of ventricular action potential duration, and its rate-dependence, and so these intervals constrain and inform models of cell electrophysiology. The parameters of models of adult human sinostrial node and ventricular cells that are based on adult cell electrophysiology and tissue molecular mapping have been modified to construct preliminary models of foetal cell electrophysiology, which reproduce these intervals from fECG recordings. The PR and QR intervals provide an index of conduction times, and hence propagation velocities (approx. 1–10 cm s −1 , increasing during gestation) and so inform models of tissue electrophysiology. Although the developing foetal heart is small and the cells are weakly coupled, it can support potentially lethal re-entrant arrhythmia.

REENTRY IN AN ANATOMICAL MODEL OF THE HUMAN VENTRICLES

2003 ◽  
Vol 13 (12) ◽  
pp. 3693-3702 ◽  
Author(s):  
O. BERNUS ◽  
H. VERSCHELDE ◽  
A. V. PANFILOV
Keyword(s):  
Cardiac Tissue ◽  
Interventricular Septum ◽  
Three Dimensional ◽  
Polymorphic Ventricular Tachycardia ◽  
Ionic Model ◽  
Single Vortex ◽  
Activation Patterns ◽  
Ventricular Tissue ◽  
Model Complex ◽  
The Right

We study wave propagation in a recently developed model, which reproduces geometry and fiber orientation in the right and left ventricles of the human heart. The cardiac tissue is represented using the previously developed γ-ionic model for human ventricular tissue using a spatial resolution of 0.5 mm. We simulate three-dimensional reentrant behavior resulting from a single vortex located in the free wall of the right, left ventricles and in the interventricular septum. We found that single reentrant scroll waves can generate V-shaped collision areas and in some cases, epicardial breakthrough patterns. The simulated ECGs of single spiral waves show similarities with monomorphic and polymorphic ventricular tachycardia, depending on the location of the reentrant sources. We model complex activation patterns resembling ventricular fibrillation by simulating the effects of an ATP-sensitive potassium channel opener and find that VF is, in that case, organized by a small number of vortices.

Multistability of reentrant rhythms in an ionic model of a two-dimensional annulus of cardiac tissue

2005 ◽  
Vol 72 (5) ◽  
Author(s):  
Philippe Comtois ◽  
Alain Vinet
Keyword(s):  
Cardiac Tissue ◽  
Two Dimensional ◽  
Ionic Model

scholarly journals Efficient high order schemes for stiff ODEs in cardiac electrophysiology

2018 ◽  
Vol Volume 28 - 2018 - 2019 -... ◽  
Author(s):  
Charlie Douanla Lontsi ◽  
Yves Coudière ◽  
Charles Pierre
Keyword(s):  
Cardiac Electrophysiology ◽  
Large Time ◽  
High Order ◽  
Implicit Methods ◽  
Time Step ◽  
Ionic Model ◽  
High Order Schemes ◽  
Ventricular Cells ◽  
Stiff Odes ◽  
The Cost

International audience In this work we analyze the resort to high order exponential solvers for stiff ODEs in the context of cardiac electrophysiology modeling. The exponential Adams-Bashforth and the Rush-Larsen schemes will be considered up to order 4. These methods are explicit multistep schemes.The accuracy and the cost of these methods are numerically analyzed in this paper and benchmarked with several classical explicit and implicit schemes at various orders. This analysis has been led considering data of high particular interest in cardiac electrophysiology : the activation time ($t_a$ ), the recovery time ($t_r $) and the action potential duration ($APD$). The Beeler Reuter ionic model, especially designed for cardiac ventricular cells, has been used for this study. It is shown that, in spite of the stiffness of the considered model, exponential solvers allow computation at large time steps, as large as for implicit methods. Moreover, in terms of cost for a given accuracy, a significant gain is achieved with exponential solvers. We conclude that accurate computations at large time step are possible with explicit high order methods. This is a quite important feature when considering stiff non linear ODEs. Dans ce travail, nous analysons le recours aux solveurs exponentiels d’ordre élevé pourdes EDO raides dans le contexte de la modélisation en électrophysiologie cardiaque. Nous nousintéressons en particulier aux schémas exponentiels Adams Bashforth et Rush Larsen de l’ordre 2à 4. Ces schémas sont explicites et multi-pas. La précision et le coût de ces méthodes sont analysésnumériquement et comparés avec plusieurs schémas explicites et implicites classiques à diversordres. Cette analyse nous permet de calculer des valeurs informatives qui ont un interêt particulieren électrophysiologie cardiaque: Le temps d’activation (ta), le temps de restitution (tr) et la durée dupotentiel d’action (APD). L’étude est faite à travers le modèle ionique Beeler Reuter, spécialementconçu pour les cellules ventriculaires cardiaques. Nous montrons que malgré la raideur des équations,les schémas exponentiels permettent de faire des calculs à des pas de temps aussi grand quepour des schémas implicites. De plus pour une précision donnée, un gain significatif en terme de coûtest obtenu avec des solveurs exponentiels. Nous concluons qu’il est possible de faire des calculsprécis à des grands échelles de temps avec des schémas explicites d’ordre élevé. Ce qui est unecaractéristique très importante quand il s’agit des EDO raides et non linéaires.

scholarly journals Optimisation of Ionic Models to Fit Tissue Action Potentials: Application to 3D Atrial Modelling

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Amr Al Abed ◽  
Tianruo Guo ◽  
Nigel H. Lovell ◽  
Socrates Dokos
Keyword(s):  
Action Potentials ◽  
Cardiac Tissue ◽  
Superior Vena ◽  
Pulmonary Veins ◽  
Vena Cava ◽  
Ionic Current ◽  
Time Dependent ◽  
Ionic Model ◽  
Electrophysiological Properties

A 3D model of atrial electrical activity has been developed with spatially heterogeneous electrophysiological properties. The atrial geometry, reconstructed from the male Visible Human dataset, included gross anatomical features such as the central and peripheral sinoatrial node (SAN), intra-atrial connections, pulmonary veins, inferior and superior vena cava, and the coronary sinus. Membrane potentials of myocytes from spontaneously active or electrically pacedin vitrorabbit cardiac tissue preparations were recorded using intracellular glass microelectrodes. Action potentials of central and peripheral SAN, right and left atrial, and pulmonary vein myocytes were each fitted using a generic ionic model having three phenomenological ionic current components: one time-dependent inward, one time-dependent outward, and one leakage current. To bridge the gap between the single-cell ionic models and the gross electrical behaviour of the 3D whole-atrial model, a simplified 2D tissue disc with heterogeneous regions was optimised to arrive at parameters for each cell type under electrotonic load. Parameters were then incorporated into the 3D atrial model, which as a result exhibited a spontaneously active SAN able to rhythmically excite the atria. The tissue-based optimisation of ionic models and the modelling process outlined are generic and applicable to image-based computer reconstruction and simulation of excitable tissue.

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