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 Rotational Activity Around an Obstacle in 2D Cardiac Tissue in Presence of Cellular Heterogeneity

2021 ◽  
Author(s):  
Pavel Konovalov ◽  
Daria Mangileva ◽  
Arsenii Dokuchaev ◽  
Olga Solovyova ◽  
Alexander Panfilov
Keyword(s):  
Numerical Study ◽  
Plane Layer ◽  
Cellular Heterogeneity ◽  
Border Zone ◽  
Myocardial Tissue ◽  
Gray Zone ◽  
Tissue Heterogeneity ◽  
Ionic Model ◽  
Electrophysiological Properties ◽  
Wave Rotation

Waves of electrical excitation rotating around an obstacle is one of the important mechanisms of dangerous cardiac arrhythmias occurring in the heart damaged by post-infarction scar. Such a scar also has a border zone around it, which has electrophysiological properties different from the rest of normal myocardial tissue. Spatial patterns of wave rotation in the presence of such tissue heterogeneity are poorly studied. In this paper we perform a comprehensive numerical study of various regimes of rotation of a wave in a plane layer of the ventricular tissue around an obstacle surrounded by a gray zone. We use a TP06 cellular ionic model which reproduces the electrophysiological properties cardiomyocytes in the left ventricle of human heart. We vary the extent of obstacle and gray zone and study the pattern of wave rotation and its period. We observed different regimes of wave rotation that can be subdivided into several classes: (1) functional rotation and (2) scar rotation regimes, which were identified in the previous studies, and new (3) gray zone rotation regime: where the wave instead of rotation around the obstacle, rotates around the gray zone (an area of tissue heterogeneity) itself. For each class, the period of rotation is determined by different factors, which we discuss and quantify. We also found that due to regional pathological remodeling of myocardial tissue, we can obtain additional regimes associated with dynamical instabilities of two types which may affect or not affect the period of rotation.

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.

scholarly journals Accelerating mono-domain cardiac electrophysiology simulations using OpenCL

2015 ◽  
Vol 1 (1) ◽  
pp. 413-417
Author(s):  
Eike M. Wülfers ◽  
Zhasur Zhamoliddinov ◽  
Olaf Dössel ◽  
Gunnar Seemann
Keyword(s):  
Cardiac Electrophysiology ◽  
Cardiac Tissue ◽  
Ionic Currents ◽  
Domain Model ◽  
Electrical Excitation ◽  
Simulation Domain ◽  
Speed Up ◽  
Cross Platform ◽  
Atrial Myocyte ◽  
Intel Xeon

AbstractUsing OpenCL, we developed a cross-platform software to compute electrical excitation conduction in cardiac tissue. OpenCL allowed the software to run parallelized and on different computing devices (e.g., CPUs and GPUs). We used the macroscopic mono-domain model for excitation conduction and an atrial myocyte model by Courtemanche et al. for ionic currents. On a CPU with 12 HyperThreading-enabled Intel Xeon 2.7 GHz cores, we achieved a speed-up of simulations by a factor of 1.6 against existing software that uses OpenMPI. On two high-end AMD FirePro D700 GPUs the OpenCL software ran 2.4 times faster than the OpenMPI implementation. The more nodes the discretized simulation domain contained, the higher speed-ups were achieved.

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.

scholarly journals The Role of Lipopolysaccharide-Induced Extracellular Vesicles in Cardiac Cell Death

Biology ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 69 ◽  
Author(s):  
Courtnee’ R. Bell ◽  
Leandra B. Jones ◽  
Brennetta J. Crenshaw ◽  
Sanjay Kumar ◽  
Glenn C. Rowe ◽  
...  
Keyword(s):  
Cell Death ◽  
Bacterial Infections ◽  
Cardiac Tissue ◽  
Cell Injury ◽  
Plaque Rupture ◽  
Relative Size ◽  
Cardiac Cell ◽  
Gram Negative ◽  
Human Cardiomyocytes ◽  
The Impact

Exosomes play a crucial role in the progression of infectious diseases, as exosome release and biogenesis are affected by external factors, such as pathogenic infections. Pyrogens may aide in the progression of diseases by triggering inflammation, endothelial cell injury, and arterial plaque rupture, all of which can lead to acute coronary disease, resulting in cardiac tissue death and the onset of a cardiac event (CE). To better understand the effects of Gram-negative bacterial infections on exosome composition and biogenesis, we examined exosome characteristics after treatment of AC16 human cardiomyocytes with lipopolysaccharide (LPS), which served as a model system for Gram-negative bacterial infection. Using increasing doses (0, 0.1, 1, or 10 µg) of LPS, we showed that treatment with LPS substantially altered the composition of AC16-derived exosomes. Both the relative size and the quantity (particles/mL) of exosomes were decreased significantly at all tested concentrations of LPS treatment compared to the untreated group. In addition, LPS administration reduced the expression of exosomal proteins that are related to exosomal biogenesis. Conversely, we observed an increase in immunomodulators present after LPS administration. This evaluation of the impact of LPS on cardiac cell death and exosome composition will yield new insight into the importance of exosomes in a variety of physiological and pathological processes as it relates to disease progression, diagnosis, and treatment.

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.

scholarly journals Nesfatin-1 in Human and Murine Cardiomyocytes: Synthesis, Secretion, and Mobilization of GLUT-4

Endocrinology ◽  
2013 ◽  
Vol 154 (12) ◽  
pp. 4757-4767 ◽  
Author(s):  
Sandra Feijóo-Bandín ◽  
Diego Rodríguez-Penas ◽  
Vanessa García-Rúa ◽  
Ana Mosquera-Leal ◽  
Manuel Francisco Otero ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Intracellular Signaling ◽  
Energy Homeostasis ◽  
Glucose Transporter ◽  
Cardiac Tissue ◽  
Western Blots ◽  
Human Cardiomyocytes ◽  
Glut 4 ◽  
Confocal Immunofluorescence Microscopy ◽  
Cultured Cardiomyocytes

Nesfatin-1, a satiety-inducing peptide identified in hypothalamic regions that regulate energy balance, is an integral regulator of energy homeostasis and a putative glucose-dependent insulin coadjuvant. We investigated its production by human cardiomyocytes and its effects on glucose uptake, in the main cardiac glucose transporter GLUT-4 and in intracellular signaling. Quantitative RT-PCR, Western blots, confocal immunofluorescence microscopy, and ELISA of human and murine cardiomyocytes and/or cardiac tissue showed that cardiomyocytes can synthesize and secrete nesfatin-1. Confocal microscopy of cultured cardiomyocytes after GLUT-4 labeling showed that nesfatin-1 mobilizes this glucose transporter to cell peripherals. The rate of 2-deoxy-d-[3H]glucose incorporation demonstrated that nesfatin-1 induces glucose uptake by HL-1 cells and cultured cardiomyocytes. Nesfatin-1 induced dose- and time-dependent increases in the phosphorylation of ERK1/2, AKT, and AS160. In murine and human cardiac tissue, nesfatin-1 levels varied with diet and coronary health. In conclusion, human and murine cardiomyocytes can synthesize and secrete nesfatin-1, which is able to induce glucose uptake and the mobilization of the glucose transporter GLUT-4 in these cells. Nesfatin-1 cardiac levels are regulated by diet and coronary health.

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