scholarly journals A Simplified 3D Model of Whole Heart Electrical Activity and 12-Lead ECG Generation

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Siniša Sovilj ◽  
Ratko Magjarević ◽  
Nigel H. Lovell ◽  
Socrates Dokos
Keyword(s):  
Electrical Activity ◽  
Three Dimensional ◽  
Model Complexity ◽  
Bidomain Model ◽  
Computationally Efficient ◽  
Lead System ◽  
Heart Electrical Activity ◽  
Cell Tissue ◽  
Whole Heart ◽  
Electrocardiogram Ecg

We present a computationally efficient three-dimensional bidomain model of torso-embedded whole heart electrical activity, with spontaneous initiation of activation in the sinoatrial node, incorporating a specialized conduction system with heterogeneous action potential morphologies throughout the heart. The simplified geometry incorporates the whole heart as a volume source, with heart cavities, lungs, and torso as passive volume conductors. We placed four surface electrodes at the limbs of the torso: , , and and six electrodes on the chest to simulate the Einthoven, Goldberger-augmented and precordial leads of a standard 12-lead system. By placing additional seven electrodes at the appropriate torso positions, we were also able to calculate the vectorcardiogram of the Frank lead system. Themodel was able to simulate realistic electrocardiogram (ECG) morphologies for the 12 standard leads, orthogonal , , and leads, as well as the vectorcardiogram under normal and pathological heart states. Thus, simplified and easy replicable 3D cardiac bidomain model offers a compromise between computational load and model complexity and can be used as an investigative tool to adjust cell, tissue, and whole heart properties, such as setting ischemic lesions or regions of myocardial infarction, to readily investigate their effects on whole ECG morphology.

scholarly journals Simplified 2D Bidomain Model of Whole Heart Electrical Activity and ECG Generation

2014 ◽  
Vol 14 (3) ◽  
pp. 136-143 ◽  
Author(s):  
Siniša Sovilj ◽  
Ratko Magjarević ◽  
Amr Al Abed ◽  
Nigel H. Lovell ◽  
Socrates Dokos
Keyword(s):  
Electrical Activity ◽  
Sinoatrial Node ◽  
Biophysical Model ◽  
Model Complexity ◽  
Lead System ◽  
Heart Electrical Activity ◽  
Cardiac Model ◽  
Surface Ecg ◽  
Whole Heart ◽  
Ecg Morphology

Abstract The aim of this study was the development of a geometrically simple and highly computationally-efficient two dimensional (2D) biophysical model of whole heart electrical activity, incorporating spontaneous activation of the sinoatrial node (SAN), the specialized conduction system, and realistic surface ECG morphology computed on the torso. The FitzHugh-Nagumo (FHN) equations were incorporated into a bidomain finite element model of cardiac electrical activity, which was comprised of a simplified geometry of the whole heart with the blood cavities, the lungs and the torso as an extracellular volume conductor. To model the ECG, we placed four electrodes on the surface of the torso to simulate three Einthoven leads VI, VII and VIII from the standard 12-lead system. The 2D model was able to reconstruct ECG morphology on the torso from action potentials generated at various regions of the heart, including the sinoatrial node, atria, atrioventricular node, His bundle, bundle branches, Purkinje fibers, and ventricles. Our 2D cardiac model offers a good compromise between computational load and model complexity, and can be used as a first step towards three dimensional (3D) ECG models with more complex, precise and accurate geometry of anatomical structures, to investigate the effect of various cardiac electrophysiological parameters on ECG morphology.

scholarly journals Numerical simulation of mathematical heart model in COMSOL

2020 ◽  
Vol 9 (1) ◽  
pp. 77
Author(s):  
Iffat Ara
Keyword(s):  
Finite Element ◽  
Electrical Activity ◽  
The Body ◽  
Reaction Diffusion Equations ◽  
Element Formulation ◽  
Bidomain Model ◽  
Finite Element Software ◽  
Cardiac Electrical Activity ◽  
Cardiac Model ◽  
Whole Heart

Electrical activity is essential for the cardiac cell to perform its function. Mathematical modeling of cardiac electrical activity is performed from the cell, tissue and organ levels through to the body surface level. The electrical activity of the cardiac as a whole is thus characterized by a complex multiscale structure. The most complete model of such a complex setting is the anisotropic bidomain model that consists of a system of two degenerate parabolic reaction diffusion equations describing the intra and extracellular potentials in the cardiac muscle, coupled with a system of ordinary deferential equations describing the ionic currents flowing through the cellular membrane. This study describes an anatomically realistic 3D Bidomain model of whole-heart electrical activity. The heart was embedded in a human torso, incorporating spontaneous activation with heterogeneous action potential (AP) morphologies throughout the heart. The aim of this study is the development of a geometrically simple and computationally efficient 3D model of heart. In this paper a finite element formulation, model and simulation of Bidomain equation has been conducted. The FitzHugh-Nagumo (FHN) equations were incorporated into Bidomain model of cardiac electrical activity, which was comprised of a simplified geometry of the whole heart with the torso as an extracellular volume conductor. Laplace equation for the torso also considered. Simplified 3D cardiac model was implemented using COMSOL Multiphysics 5.0 finite element software. Electrical potential at different point on torso is measured. Propagation of electrical excitation on heart surface is also observed. This study represents the first stage toward the development of an accurate computer model of heart activation.   

scholarly journals Aortic Stiffness, Left Ventricle Hypertrophy, and Homogeneity of Ventricle Repolarization in Adult Dialyzed Patients

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Tomasz Zapolski ◽  
Andrzej Jaroszyński ◽  
Anna Drelich-Zbroja ◽  
Anna Wysocka ◽  
Jacek Furmaga ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Aortic Stiffness ◽  
Three Dimensional ◽  
Study Group ◽  
Strong Correlations ◽  
Aortic Compliance ◽  
Dialysis Patients ◽  
Heart Electrical Activity ◽  
Left Ventricle Hypertrophy ◽  
Ventricle Hypertrophy

Aim. Study was designed to assess relationship between aortic compliance and homogeneity of heart electrical activity in dialysis patients.Methods. Study group was consisted of 120 dialyzed patients; 57 (age ) were on continuous ambulatory peritoneal dialysis (CAPD) and 73 (age ) were hemodialyzed (HD). Three-dimensional vectorocardiographic (VCG) monitoring was done to assess: QRS-, and . Echocardiography was performed to assess: , , ASI (aortic siffness index).Results. ASI in HD as well as in CAPD patients was significantly higher compared to controls [resp., 5,51 (±1,32), 5,83 (±1,41), 3,07 (±1,09)]. Cut-off value of ASI was 5,67. In HD patients strong correlations between ASI and QRS-, and were determined (resp., , ; , and , ). In CAPD group were significant association between ASI and QRS-, and (resp., , ; , and , ). ASI was independently and markedly associated with: QRS-, , , ADMA, cTnT, CRP, Total-chol, LDL-chol in HD and CAPD patients.Conclusions. ASI and VCG indices are higher in HD and CAPD patients. Correlation between ASI and VCG parameters may reflect unfavourable influence of poor aortic compliance on the electrical activity of the heart in dialyzed patients. Hypertrophy aggravates repolarization disturbances in hemodialyzed patients.

scholarly journals Filament Dynamics during Simulated Ventricular Fibrillation in a High-Resolution Rabbit Heart

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Pras Pathmanathan ◽  
Richard A. Gray
Keyword(s):  
High Resolution ◽  
Ventricular Fibrillation ◽  
Electrical Activity ◽  
Three Dimensional ◽  
Coronary Vessels ◽  
Rabbit Heart ◽  
Filament Dynamics ◽  
Surface Patterns ◽  
Time Specific ◽  
Whole Heart

The mechanisms underlying ventricular fibrillation (VF) are not well understood. The electrical activity on the heart surface during VF has been recorded extensively in the experimental setting and in some cases clinically; however, correspondingtransmuralactivation patterns are prohibitively difficult to measure. In this paper, we use a high-resolution biventricular heart model to study three-dimensional electrical activity during fibrillation, focusing on the driving sources of VF: “filaments,” the organising centres of unstable reentrant scroll waves. We show, for the first time, specific 3D filamentdynamicsduring simulated VF in a whole heart geometry that includes fine-scale anatomical structures. Our results suggest that transmural activity is much more complex than what would be expected from surface observations alone. We present examples of complex intramural activity, including filament breakup and reattachment, anchoring to the thin right ventricular apex; rapid transitions among various filament shapes; and filament lengths much greater than wall thickness. We also present evidence for anatomy playing a major role in VF development and coronary vessels and trabeculae influencing filament dynamics. Overall, our results indicate that intramural activity during simulated VF is extraordinarily complex and suggest that further investigation of 3D filaments is necessary to fully comprehend recorded surface patterns.

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.

scholarly journals Elastic transformation of histological slices allows precise co-registration with microCT data sets for a refined virtual histology approach

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jonas Albers ◽  
Angelika Svetlove ◽  
Justus Alves ◽  
Alexander Kraupner ◽  
Francesca di Lillo ◽  
...  
Keyword(s):  
Three Dimensional ◽  
High Specificity ◽  
Histopathological Analysis ◽  
Specific Information ◽  
Data Sets ◽  
Virtual Histology ◽  
Novel Approach ◽  
Cell Tissue ◽  
Immuno Histochemistry ◽  
3D Information

AbstractAlthough X-ray based 3D virtual histology is an emerging tool for the analysis of biological tissue, it falls short in terms of specificity when compared to conventional histology. Thus, the aim was to establish a novel approach that combines 3D information provided by microCT with high specificity that only (immuno-)histochemistry can offer. For this purpose, we developed a software frontend, which utilises an elastic transformation technique to accurately co-register various histological and immunohistochemical stainings with free propagation phase contrast synchrotron radiation microCT. We demonstrate that the precision of the overlay of both imaging modalities is significantly improved by performing our elastic registration workflow, as evidenced by calculation of the displacement index. To illustrate the need for an elastic co-registration approach we examined specimens from a mouse model of breast cancer with injected metal-based nanoparticles. Using the elastic transformation pipeline, we were able to co-localise the nanoparticles to specifically stained cells or tissue structures into their three-dimensional anatomical context. Additionally, we performed a semi-automated tissue structure and cell classification. This workflow provides new insights on histopathological analysis by combining CT specific three-dimensional information with cell/tissue specific information provided by classical histology.

scholarly journals Three-dimensional hydrostratigraphy and groundwater flow models in complex Quaternary deposits and weathered/fractured bedrock: evaluating increasing model complexity

2021 ◽  
Author(s):  
Susanne Charlotta Åberg ◽  
Annika Katarina Åberg ◽  
Kirsti Korkka-Niemi
Keyword(s):  
Groundwater Flow ◽  
Three Dimensional ◽  
Model Complexity ◽  
Quaternary Sediments ◽  
Fractured Bedrock ◽  
Flow Models ◽  
Flow Modelling ◽  
Crystalline Bedrock ◽  
Discharge Patterns ◽  
Geological Units

AbstractGreater complexity in three-dimensional (3D) model structures yields more plausible groundwater recharge/discharge patterns, especially in groundwater/surface-water interactions. The construction of a 3D hydrostratigraphic model prior to flow modelling is beneficial when the hydraulic conductivity of geological units varies considerably. A workflow for 3D hydrostratigraphic modelling with Leapfrog Geo and flow modelling with MODFLOW-NWT was developed. It was used to evaluate how the modelling results for groundwater flow and recharge/discharge patterns differ when using simple or more complex hydrostratigraphic models. The workflow was applied to a study site consisting of complex Quaternary sediments underlain by fractured and weathered crystalline bedrock. Increasing the hydrostratigraphic detail appeared to improve the fit between the observed and simulated water table, and created more plausible groundwater flow patterns. Interlayered zones of low and high conductivity disperse the recharge/discharge patterns, increasing the vertical flow component. Groundwater flow was predominantly horizontal in models in which Quaternary sediments and bedrock were simplified as one layer per unit. It appears to be important to define the interlayered low-conductivity units, which can limit groundwater infiltration and also affect groundwater discharge patterns. Explicit modelling with Leapfrog Geo was found to be effective but time-consuming in the generation of scattered and thin-layered strata.

scholarly journals Forest Height Estimation Based on P-Band Pol-InSAR Modeling and Multi-Baseline Inversion

2020 ◽  
Vol 12 (8) ◽  
pp. 1319
Author(s):  
Xiaofan Sun ◽  
Bingnan Wang ◽  
Maosheng Xiang ◽  
Liangjiang Zhou ◽  
Shuai Jiang
Keyword(s):  
Standard Deviation ◽  
Vertical Structure ◽  
Incidence Angle ◽  
Three Dimensional ◽  
Solution Space ◽  
Model Complexity ◽  
Two Dimensional ◽  
Dimensional Parameter ◽  
Model Inversion ◽  
Forest Height

The Gaussian vertical backscatter (GVB) model has a pivotal role in describing the forest vertical structure more accurately, which is reflected by P-band polarimetric interferometric synthetic aperture radar (Pol-InSAR) with strong penetrability. The model uses a three-dimensional parameter space (forest height, Gaussian mean representing the strongest backscattered power elevation, and the corresponding standard deviation) to interpret the forest vertical structure. This paper establishes a two-dimensional GVB model by simplifying the three-dimensional one. Specifically, the two-dimensional GVB model includes the following three cases: the Gaussian mean is located at the bottom of the canopy, the Gaussian mean is located at the top of the canopy, as well as a constant volume profile. In the first two cases, only the forest height and the Gaussian standard deviation are variable. The above approximation operation generates a two-dimensional volume only coherence solution space on the complex plane. Based on the established two-dimensional GVB model, the three-baseline inversion is achieved without the null ground-to-volume ratio assumption. The proposed method improves the performance by 18.62% compared to the three-baseline Random Volume over Ground (RVoG) model inversion. In particular, in the area where the radar incidence angle is less than 0.6 rad, the proposed method improves the inversion accuracy by 34.71%. It suggests that the two-dimensional GVB model reduces the GVB model complexity while maintaining a strong description ability.

Sign in / Sign up

Export Citation Format

Share Document