Comparison of a Derived ECG from a Cardioware Harness to a Standard 12-Lead ECG During Rest and Exercise

Purpose: To determine whether a 12-lead electrocardiogram (ECG) using five dry electrodes in the modified EASI electrode position in the CardioWare harness can be derived from a standard 12-lead ECG during rest, ambulatory walking, and strenuous walking on a treadmill. Methods: Thirty healthy men (n=15) and women (n=15), ages 20-54 years, from Cleveland State University and the surrounding community participated in this study. Each subject served as their own control as they were connected to both types of ECG simultaneously (Modified EASI CardioWare and Standard Mason-Likar). Data was collected from both ECG placements for five minutes of rest (Trial A) and during Trial B for two intensities of exercise. The first half of Trial B included rest and ambulatory walking (Stage 1: standing rest and Stage 2: walking 1.7mph, 0 incline). The second half of Trial B consisted of strenuous walking and recovery (Stage 3: walking 1.7mph, 10 incline, Stage 4: walking 2.5mph, 12 incline, and Stage 5: standing recovery). Paired samples t-tests were used to compare the two electrode placements. Results: There was no significant difference between the root mean square error (RMSE) of the two different types of electrode placements during either the first half or the second half of Trial B (p \u3e .05). All correlations were robust (r range= 0.658 - 0.942) and significant (p =0.0001). The subjective goodness of fit measure based on the overlay of both types of ECGs was similar. Conclusions. It can be concluded that the modified EASI derived 12-lead ECG is an acceptable alternative to the standard 12-lead ML system at rest, ambulatory, and strenuous walkin

Comparison of a Derived ECG from a Cardioware Harness to a Standard 12-Lead ECG During Rest and Exercise

Purpose: To determine whether a 12-lead electrocardiogram (ECG) using five dry electrodes in the modified EASI electrode position in the CardioWare harness can be derived from a standard 12-lead ECG during rest, ambulatory walking, and strenuous walking on a treadmill. Methods: Thirty healthy men (n=15) and women (n=15), ages 20-54 years, from Cleveland State University and the surrounding community participated in this study. Each subject served as their own control as they were connected to both types of ECG simultaneously (Modified EASI CardioWare and Standard Mason-Likar). Data was collected from both ECG placements for five minutes of rest (Trial A) and during Trial B for two intensities of exercise. The first half of Trial B included rest and ambulatory walking (Stage 1: standing rest and Stage 2: walking 1.7mph, 0 incline). The second half of Trial B consisted of strenuous walking and recovery (Stage 3: walking 1.7mph, 10 incline, Stage 4: walking 2.5mph, 12 incline, and Stage 5: standing recovery). Paired samples t-tests were used to compare the two electrode placements. Results: There was no significant difference between the root mean square error (RMSE) of the two different types of electrode placements during either the first half or the second half of Trial B (p \u3e .05). All correlations were robust (r range= 0.658 - 0.942) and significant (p =0.0001). The subjective goodness of fit measure based on the overlay of both types of ECGs was similar. Conclusions. It can be concluded that the modified EASI derived 12-lead ECG is an acceptable alternative to the standard 12-lead ML system at rest, ambulatory, and strenuous walkin

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 159

This bibliography lists 257 reports, articles, and other documents introduced into the NASA scientific and technical information system in September 1976

Multiscale Modeling of Cardiac Electrophysiology: Adaptation to Atrial and Ventricular Rhythm Disorders and Pharmacological Treatment

Multiscale modeling of cardiac electrophysiology helps to better understand the underlying mechanisms of atrial fibrillation, acute cardiac ischemia and pharmacological treatment. For this purpose, measurement data reflecting these conditions have to be integrated into models of cardiac electrophysiology. Several methods for this model adaptation are introduced in this thesis. The resulting effects are investigated in multiscale simulations ranging from the ion channel up to the body surface

ECG-Based Detection of Early Myocardial Ischemia in a Computational Model: Impact of Additional Electrodes, Optimal Placement, and a New Feature for ST Deviation

In case of chest pain, immediate diagnosis of myocardial ischemia is required to respond with an appropriate treatment. The diagnostic capability of the electrocardiogram (ECG), however, is strongly limited for ischemic events that do not lead to ST elevation. This computational study investigates the potential of different electrode setups in detecting early ischemia at 10 minutes after onset: standard 3-channel and 12-lead ECG as well as body surface potential maps (BSPMs). Further, it was assessed if an additional ECG electrode with optimized position or the right-sided Wilson leads can improve sensitivity of the standard 12-lead ECG. To this end, a simulation study was performed for 765 different locations and sizes of ischemia in the left ventricle. Improvements by adding a single, subject specifically optimized electrode were similar to those of the BSPM: 2-11% increased detection rate depending on the desired specificity. Adding right-sided Wilson leads had negligible effect. Absence of ST deviation could not be related to specific locations of the ischemic region or its transmurality. As alternative to the ST time integral as a feature of ST deviation, the K point deviation was introduced: the baseline deviation at the minimum of the ST-segment envelope signal, which increased 12-lead detection rate by 7% for a reasonable threshold. © 2015 Axel Loewe et al

A staggered-in-time and non-conforming-in-space numerical framework for realistic cardiac electrophysiology outputs

Computer-based simulations of non-invasive cardiac electrical outputs, such as electrocardiograms and body surface potential maps, usually entail severe computational costs due to the need of capturing fine-scale processes and to the complexity of the heart-torso morphology. In this work, we model cardiac electrical outputs by employing a coupled model consisting of a reaction-diffusion model - either the bidomain model or the most efficient pseudo-bidomain model - on the heart, and an elliptic model in the torso. We then solve the coupled problem with a segregated and staggered in-time numerical scheme, that allows for independent and infrequent solution in the torso region. To further reduce the computational load, main novelty of this work is in introduction of an interpolation method at the interface between the heart and torso domains, enabling the use of non-conforming meshes, and the numerical framework application to realistic cardiac and torso geometries. The reliability and efficiency of the proposed scheme is tested against the corresponding state-of-the-art bidomain-torso model. Furthermore, we explore the impact of torso spatial discretization and geometrical non-conformity on the model solution and the corresponding clinical outputs. The investigation of the interface interpolation method provides insights into the influence of torso spatial discretization and of the geometrical non-conformity on the simulation results and their clinical relevance.Comment: 26 pages,11 figures, 3 table

The Application of Computer Techniques to ECG Interpretation

This book presents some of the latest available information on automated ECG analysis written by many of the leading researchers in the field. It contains a historical introduction, an outline of the latest international standards for signal processing and communications and then an exciting variety of studies on electrophysiological modelling, ECG Imaging, artificial intelligence applied to resting and ambulatory ECGs, body surface mapping, big data in ECG based prediction, enhanced reliability of patient monitoring, and atrial abnormalities on the ECG. It provides an extremely valuable contribution to the field

Abnormal Tissue Zone Detection and Average Active Stress Estimation in Patients with LV Dysfunction

Detection of regional ventricular dysfunction is a challenging problem. This study presents an efficient method based on ultrasound (US) imaging and finite element (FE) analysis, for detecting akinetic and dyskinetic regions in the left ventricle (LV). The underlying hypothesis is that the contraction of a healthy LV is approximately homogeneous. Therefore, any deviations between the image-based measured deformation and a homogeneous contraction FE model should correspond to a pathological region. The method was first successfully applied to synthetic data simulating an acute ischemia; it demonstrated that the pathological areas were revealed with a higher contrast than those observed directly in the deformation maps. The technique was then applied to a cohort of eight left bundle branch block (LBBB) patients. For this group, the heterogeneities were significantly less pronounced than those revealed for the synthetic cases but the method was still able to identify the abnormal regions of the LV. This study indicated the potential clinical utility of the method by its simplicity in a patient-specific context and its ability to quickly identify various heterogeneities in LV function. Further studies are required to determine the model accuracy in other pathologies and to investigate its robustness to noise and image artifacts

Doctor of Philosophy

dissertationComputational simulation has become an indispensable tool in the study of both basic mechanisms and pathophysiology of all forms of cardiac electrical activity. Because the heart is comprised of approximately 4 billion electrically active cells, it is not possible to geometrically model or computationally simulate each individual cell. As a result computational models of the heart are, of necessity, abstractions that approximate electrical behavior at the cell, tissue, and whole body level. The goal of this PhD dissertation was to evaluate several aspects of these abstractions by exploring a set of modeling approaches in the field of cardiac electrophysiology and to develop means to evaluate both the amplitude of these errors from a purely technical perspective as well as the impacts of those errors in terms of physiological parameters. The first project used subject specific models and experiments with acute myocardial ischemia to show that one common simplification used to model myocardial ischemia-the simplest form of the border zone between healthy and ischemic tissue-was not supported by the experimental results. We propose a alternative approximation of the border zone that better simulates the experimental results. The second study examined the impact of simplifications in geometric models on simulations of cardiac electrophysiology. Such models consist of a connected mesh of polygonal elements and must often capture complex external and internal boundaries. A conforming mesh contains elements that follow closely the shapes of boundaries; nonconforming meshes fit the boundaries only approximately and are easier to construct but their impact on simulation accuracy has, to our knowledge, remained unknown. We evaluated the impact of this simplification on a set of three different forms of bioelectric field simulations. The third project evaluated the impact of an additional geometric modeling error; positional uncertainty of the heart in simulations of the ECG. We applied a relatively novel and highly efficient statistical approach, the generalized Polynomial Chaos-Stochastic Collocation method (gPC-SC), to a boundary element formulation of the electrocardiographic forward problem to carry out the necessary comprehensive sensitivity analysis. We found variations large enough to mask or to mimic signs of ischemia in the ECG