Ivan Tomasic

Synthesis of the 12-Lead Electrocardiogram From Differential Leads

A new approach is proposed for synthesizing the standard 12-lead ECG from three differential leads formed by pairs of proximal electrodes on the body surface. The method is supported by a statistical analysis that gives the best personalized positions of electrodes. The measurements from multichannel ECGs were used to calculate the differential leads. Our algorithm searches for optimal differential leads and the corresponding personalized transformation matrix that is used to synthesize the standard 12-lead ECG. The algorithm has been evaluated on 99 multichannel ECGs measured on 30 healthy subjects and 35 patients scheduled for elective cardiac surgery. It is shown that the algorithm significantly outperforms the synthesis based on the EASI lead system with medians of correlation coefficients greater than 0.954 for all 12 standard leads. To determine the optimal number of differential leads, the syntheses for two, three, and four differential leads were calculated. The analysis shows that 3 is the optimal number of differential leads for practical applications. Because of the proximity of the differential electrodes, the proposed approach offers an opportunity for the synthesis of a standard 12-lead ECG with wireless electrodes.

Electrocardiographic Systems With Reduced Numbers of Leads—Synthesis of the 12-Lead ECG

Systems with reduced numbers of leads that can synthesize the 12-lead electrocardiogram (ECG) with an insignificant or a small loss of diagnostic information have been proposed. The advantage over standard 12-lead ECG systems is the smaller number of measurement sites (i.e., electrodes) and, consequently, fewer wires. In this paper, we review all the important systems with reduced numbers of leads together with the methodology for synthesizing the leads. The fundamental theoretical background necessary to understand the most important concepts related to the synthesis is included. The presented theoretical and experimental justifications for the synthesis show that it is not necessary to measure a large number of leads directly, because the standard 12-lead ECG and arbitrary additional leads can be synthesized. Various approaches to evaluating the synthesized 12-lead ECG are defined and explained, and a number of systems that synthesize 12-lead ECG are presented as they were introduced in the literature. We cover the developments and improvements from the 1940s to the present day. The systems are classified on the basis of the synthesis method used, the approach to the evaluation of the synthesized ECG (depending on the measurement sites used), and on the number and types of leads employed. Based on a detailed assessment of state-of-the-art systems, open problems and challenges are highlighted, while further developments of electrocardiographic systems are envisaged.

Smart wireless sensor for physiological monitoring

Presented is a wireless body sensor capable of measuring local potential differences on a body surface. By using on-sensor signal processing capabilities, and developed algorithms for off-line signal processing on a personal computing device, it is possible to record single channel ECG, heart rate, breathing rate, EMG, and when three sensors are applied, even the 12-lead ECG. The sensor is portable, unobtrusive, and suitable for both inpatient and outpatient monitoring. The paper presents the sensors hardware and results of power consumption analysis. The sensors capabilities of recording various physiological parameters are also presented and illustrated. The paper concludes with envisioned sensors future developments and prospects.

Continuous remote monitoring of COPD patients—justification and explanation of the requirements and a survey of the available technologies

AbstractRemote patient monitoring should reduce mortality rates, improve care, and reduce costs. We present an overview of the available technologies for the remote monitoring of chronic obstructive pulmonary disease (COPD) patients, together with the most important medical information regarding COPD in a language that is adapted for engineers. Our aim is to bridge the gap between the technical and medical worlds and to facilitate and motivate future research in the field. We also present a justification, motivation, and explanation of how to monitor the most important parameters for COPD patients, together with pointers for the challenges that remain. Additionally, we propose and justify the importance of electrocardiograms (ECGs) and the arterial carbon dioxide partial pressure (PaCO2) as two crucial physiological parameters that have not been used so far to any great extent in the monitoring of COPD patients. We cover four possibilities for the remote monitoring of COPD patients: continuous monitoring during normal daily activities for the prediction and early detection of exacerbations and life-threatening events, monitoring during the home treatment of mild exacerbations, monitoring oxygen therapy applications, and monitoring exercise. We also present and discuss the current approaches to decision support at remote locations and list the normal and pathological values/ranges for all the relevant physiological parameters. The paper concludes with our insights into the future developments and remaining challenges for improvements to continuous remote monitoring systems. Graphical abstractᅟ

Data Flow and Collection for Remote Patients Monitoring: From Wireless Sensors through a Relational Database to a Web interface in Real Time

A reliable, secure, and real-time data collection from sensor devices to the end-user is an open research problem. Many research works have been focusing on the wireless communication level to obtain quality of service. This paper widens the problem, and provides a comprehensive system design, where it covers all the elements in a remote health monitoring application. The system collects measurements in a relational database, either through a C#.NET or a LabVIEW program. The end-user is able to observe either real-time data (i.e. with insignificant delay) or processed historical data on any web browser. We have shown that the inclusion of the relational database may impose a need for the data to be buffered before inserting into the database within a single transaction, but the buffering does not entail delays bigger than 50 ms.

Body Sensors and Electrocardiography

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Commercial ECG systems

price are net prices, subject to local VAT. Prices indicated with * include VAT for books; the €(D) includes 7% for Germany, the €(A) includes 10% for Austria. Prices indicated with ** include VAT for electronic products; 19% for Germany, 20% for Austria. All prices exclusive of carriage charges. Prices and other details are subject to change without notice. All errors and omissions excepted. R. Trobec, I. Tomašić, A. Rashkovska, M. Depolli, V. Avbelj Body Sensors and Electrocardiography

Can the Regression Trees Be Used to Model Relation Between ECG Leads

Besides the standard 12-lead ECG and the Holter monitor, today the market offers a wide range of modern ECG devices and services supported by the latest developments in ICT. This chapter is devoted to the current state-of-the-art from the area of ECG with a reduced number of leads. We focus on ECG wireless body sensors, differentiating between those that measure only heart rate and are used just for entertainment or during sport activities, and those that actually measure and analyze the ECG signal, with all its waveforms. The latter are elaborated in more detail, particularly our differential ECG sensor and its commercial version Savvy, for which we provide also a comprehensive comparison to other state-of-the-art sensors in that field. It is, however, inevitable that the state-of-the art will change in the future. The constant progress in ICT will always drive the development of new and improved ECG devices.

Principal Component Analysis of Differential Electrocardiographic Leads - A Contribution to the Synthesis of ECGs

Presented is a preliminary study that investigates regression trees application for the purpose of mapping relationship between three differential ECG leads and leads of the 12-lead ECG. The approach was evaluated on a single ECG measurement on which it was superior to two syntheses performed by universal and personalized linear transformations, in terms of correlation coefficients between the synthesized and measured leads. A prominent imperfection however is that the regression trees can output only a limited number of values equal to the number of leaf nodes. The paper indicates some ideas on how to overcome this deficiency.

Optimized Positioning of ECG Electrodes for WSN Applications

The principal component analysis (PCA) is applied on juxtaposed average beats of unipolar and differential leads (DLs), obtained from 35-lead multichannel ECGs, for assessing proportions of cardiac electrical activity variance that the leads measure. It was shown that 93% of the total 35- lead measured variance can be explained by the first three principal components (PCs). An analysis of correlations between the ECG leads and the first three PCs shows that the leads employing electrodes further to the heart pick up less of the total ECG variance. It was also demonstrated that DLs with highest correlations to the first three PCs, coincide with the universal DLs selected by our previously published ECG synthesis algorithm: BDLSA. This enables the application of the PCA in the selection of optimal DLs combinations for the ECG synthesis.