scholarly journals A space-fractional Monodomain model for cardiac electrophysiology combining anisotropy and heterogeneity on realistic geometries

2018 ◽  
Vol 362 ◽  
pp. 409-424 ◽  
Author(s):  
N. Cusimano ◽  
L. Gerardo-Giorda
Keyword(s):  
Cardiac Electrophysiology ◽  
Monodomain Model ◽  
Realistic Geometries

scholarly journals A two layers monodomain model of cardiac electrophysiology of the atria

2015 ◽  
Vol 71 (6-7) ◽  
pp. 1607-1641 ◽  
Author(s):  
Yves Coudière ◽  
Jacques Henry ◽  
Simon Labarthe
Keyword(s):  
Cardiac Electrophysiology ◽  
Monodomain Model

scholarly journals Optimal monodomain approximations of the bidomain equations used in cardiac electrophysiology

2014 ◽  
Vol 24 (06) ◽  
pp. 1115-1140 ◽  
Author(s):  
Yves Coudière ◽  
Yves Bourgault ◽  
Myriam Rioux
Keyword(s):  
Boundary Conditions ◽  
Cardiac Electrophysiology ◽  
Propagation Speed ◽  
Neumann Boundary ◽  
Test Cases ◽  
Bidomain Model ◽  
Bidomain Equations ◽  
Monodomain Model ◽  
The Difference ◽  
Computationally Intensive

The bidomain model is the current most sophisticated model used in cardiac electrophysiology. The monodomain model is a simplification of the bidomain model that is less computationally intensive but only valid under equal conductivity ratio. We propose in this paper optimal monodomain approximations of the bidomain model. We first prove that the error between the bidomain and monodomain solutions is bounded by the error ‖B - A‖ between the bidomain and monodomain conductivity operators. Optimal monodomain approximations are defined by minimizing the distance ‖B - A‖, which reduces for solutions over all ℝd to minimize the Lp norm of the difference between the operator symbols. Similarly, comparing the symbols pointwise amounts to compare the propagation of planar waves in the bidomain and monodomain models. We prove that any monodomain model properly propagates at least d planar waves in ℝd. We next consider and solve the optimal problem in the L∞ and L2 norms, the former providing minimal propagation error uniformly over all directions. The quality of these optimal monodomain approximations is compared among themselves and with other published approximations using two sets of test cases. The first one uses periodic boundary conditions to mimic propagation in ℝd while the second is based on a square domain with common Neumann boundary conditions. For the first test cases, we show that the error on the propagation speed is highly correlated with the error on the symbols. The second test cases show that domain boundaries control propagation directions, with only partial impact from the conductivity operator used.

High-Frequency Cardiac Electrophysiology

2019 ◽  
Author(s):  
Pavel Jurak ◽  
Josef Halamek ◽  
Pavel Leinveber ◽  
Filip Plesinger ◽  
Ivo Viscor ◽  
...  
Keyword(s):  
High Frequency ◽  
Cardiac Electrophysiology

Subclinical Thyroid Dysfunction and the Risk of Cardiovascular Disease

2020 ◽  
Vol 26 (43) ◽  
pp. 5617-5627
Author(s):  
Mirjana Stojković ◽  
Miloš Žarković
Keyword(s):  
Cardiovascular Disease ◽  
Risk Factor ◽  
Cardiac Electrophysiology ◽  
Vascular System ◽  
Density Lipoprotein ◽  
Thyroid Stimulating Hormone ◽  
Normal Limits ◽  
Developing Heart ◽  
Treatment Indications ◽  
Increased Risk

The prevalence of subclinical hypothyroidism (SH) is 3-10%. The prevalence of subclinical hyperthyroidism (SHr) is 0.7-9.7%. Thyroid hormones affect cardiac electrophysiology, contractility, and vasculature. SH is associated with an increased risk of coronary heart disease (CHD), especially in subjects under 65. SHr seems to be associated with a slightly increased risk of CHD and an increase in CHD-related mortality. Both SH and SHr carry an increased risk of developing heart failure (HF), especially in those under 65. Both SH and SHr are associated with worse prognoses in patients with existing HF. SH is probably not associated with atrial fibrillation (AF). SHr, low normal thyroid-stimulating hormone (TSH) and high normal free thyroxine (FT4) are all associated with the increased risk of AF. An association between endothelial dysfunction and SH seems to exist. Data regarding the influence of SHr on the peripheral vascular system are conflicting. SH is a risk factor for stroke in subjects under 65. SHr does not increase the risk of stroke. Both SH and SHr have an unfavourable effect on cardiovascular disease (CVD) and all-cause mortality. There is a U-shaped curve of mortality in relation to TSH concentrations. A major factor that modifies the relation between subclinical thyroid disease (SCTD) and mortality is age. SH increases blood pressure (BP). SHr has no significant effect on BP. Lipids are increased in patients with SH. In SHr, high-density lipoprotein cholesterol and lipoprotein( a) are increased. SCTD should be treated when TSH is over 10 mU/l or under 0.1 mU/l. Treatment indications are less clear when TSH is between normal limits and 0.1 or 10 mU/L. The current state of knowledge supports the understanding of SCTD’s role as a risk factor for CVD development. Age is a significant confounding factor, probably due to age-associated changes in the TSH reference levels.

scholarly journals Machine-readable Yin–Yang imbalance: traditional Chinese medicine syndrome computer modeling based on three-dimensional noninvasive cardiac electrophysiology imaging

2019 ◽  
Vol 47 (4) ◽  
pp. 1580-1591 ◽  
Author(s):  
Wei Cen ◽  
Ralph Hoppe ◽  
Aiwu Sun ◽  
Hongyan Ding ◽  
Ning Gu
Keyword(s):  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Electrical Activity ◽  
Computer Modeling ◽  
Cardiac Electrophysiology ◽  
Three Dimensional ◽  
Mathematical Physics ◽  
Syndrome Differentiation ◽  
Physics Model ◽  
Machine Readable

Objectives The principal diagnostic methods of traditional Chinese medicine (TCM) are inspection, auscultation and olfaction, inquiry, and pulse-taking. Treatment by syndrome differentiation is likely to be subjective. This study was designed to provide a basic theory for TCM diagnosis and establish an objective means of evaluating the correctness of syndrome differentiation. Methods We herein provide the basic theory of TCM syndrome computer modeling based on a noninvasive cardiac electrophysiology imaging technique. Noninvasive cardiac electrophysiology imaging records the heart’s electrical activity from hundreds of electrodes on the patient’s torso surface and therefore provides much more information than 12-lead electrocardiography. Through mathematical reconstruction algorithm calculations, the reconstructed heart model is a machine-readable description of the underlying mathematical physics model that reveals the detailed three-dimensional (3D) electrophysiological activity of the heart. Results From part of the simulation results, the imaged 3D cardiac electrical source provides dynamic information regarding the heart’s electrical activity at any given location within the 3D myocardium. Conclusions This noninvasive cardiac electrophysiology imaging method is suitable for translating TCM syndromes into a computable format of the underlying mathematical physics model to offer TCM diagnosis evidence-based standards for ensuring correct evaluation and rigorous, scientific data for demonstrating its efficacy.

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