Dry electrodes for electrocardiography

Physiological measurement, 2015

We designed a spandex tank top with dry electrodes for continuous electrocardiogram (ECG) recording. This pilot study determined the best fabric, the best electrode types, sizes, and locations. Optimal electrodes provide high signal to artifact ratio (SAR) and reliability by meeting the following criteria: 1) low baseline shift, 2) high adhesion, 3) good physical stability, 4) large effective area, 5) thin with high flexibility (Luo et al 1992). We compared electrodes from three main groups: Ag/AgCl gel electrode, commercial conductive rubber and foam-metal based electrodes. Ag/AgCl gel electrodes are easy to apply, make good body contact and do not slip during the course of an experiment. We found that higher SARs are obtained when electrode area is increased (40 mm diameter) and the two dry measurement electrodes are located on convex areas (over chest muscle) rather than concave areas (over sternum), so the spandex will apply light pressure to the dry electrode to yield good elec...

BioMedical Engineering OnLine, 2021

Background Continuous long-term electrocardiography monitoring has been increasingly recognized for early diagnosis and management of different types of cardiovascular diseases. To find an alternative to Ag/AgCl gel electrodes that are improper for this application scenario, many efforts have been undertaken to develop novel flexible dry textile electrodes integrated into the everyday garments. With significant progresses made to address the potential issues (e.g., low signal-to-noise ratio, high skin–electrode impedance, motion artifact, and low durability), the lack of standard evaluation procedure hinders the further development of dry electrodes (mainly the design and optimization). Results A standard testing procedure and framework for skin–electrode impedance measurement is demonstrated for the development of novel dry textile electrodes. Different representative electrode materials have been screen-printed on textile substrates. To verify the performance of dry textile electr...

IEEE Reviews in Biomedical Engineering, 2000

Recent demand and interest in wireless, mobile-based healthcare has driven significant interest towards developing alternative biopotential electrodes for patient physiological monitoring. The conventional wet adhesive Ag/AgCl electrodes used almost universally in clinical applications today provide an excellent signal but are cumbersome and irritating for mobile use. While electrodes that operate without gels, adhesives and even skin contact have been known for many decades, they have yet to achieve any acceptance for medical use. In addition, detailed knowledge and comparisons between different electrodes are not well known in the literature. In this paper, we explore the use of dry/noncontact electrodes for clinical use by first explaining the electrical models for dry, insulated and noncontact electrodes and show the performance limits, along with measured data. The theory and data show that the common practice of minimizing electrode resistance may not always be necessary and actually lead to increased noise depending on coupling capacitance. Theoretical analysis is followed by an extensive review of the latest dry electrode developments in the literature. The paper concludes with highlighting some of the novel systems that dry electrode technology has enabled for cardiac and neural monitoring followed by a discussion of the current challenges and a roadmap going forward.

Pakistan Journal of Engineering and Technology

Humans and animals both generate bioelectric signals through their tissues in static and active forms. These signals could be used to check the different physiological conditions of the body. Electrocardiogram (ECG) is one of the signals produced by the heart. ECG helps to monitor the health of the heart such as heart rate, contraction of heart muscles, and blood circulation. Abnormality in these parameters can cause serious cardiovascular diseases. Thus, monitoring of ECG helps to early diagnose cardiovascular diseases. To measure these signals electrodes or sensors are used. There are several types of electrodes are developed to measure heart bioelectric signals, but they are not very efficient, consume more power, and can harm the skin. The focus of this research was to design new and more efficient dry electrodes. For this purpose, ECG noise was simulated in MATLAB and the main schematic diagram was designed. Suitable components of the electrode were selected according to the de...

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2017

The use of wearable dry sensors for recording long term ECG signals is a requirement for certain studies of heart rhythm. Knowledge of the skin-electrode electrical performance of dry electrodes is necessary when seeking to improve various processing stages for signal quality enhancement. In this paper, methods for the assessment of dry skin-electrode impedance (ZSE) and its modelling are presented. Measurements were carried out on selected electrode materials such as silver, stainless steel, AgCl (dry) and polyurethane. These had ZSE values between 500 kΩ and 1 MΩ within the main ECG frequency range (1 Hz - 100 Hz); in contrast to plain iron material which had a significantly higher impedance. However, in spite of the high ZSE values, open bandwidth ECG traces were of acceptable quality and stability; with dry AgCl material offering the best ECG trace performance.

Advances in Electrocardiograms - Methods and Analysis, 2012

2011

The design and fabrication of a novel 2-scale topography dry electrode using macro and micro needles is presented. The macro needles enable biopotential measurements on hairy skin, the function of the micro needles is to decrease the electrode impedance even further by penetrating the outer skin layer. Also, a fast and reliable impedance characterization protocol is described. Based on this impedance measurement protocol, a comparison study is made between our dry electrode, 3 other commercial dry electrodes and a standard wet gel electrode. Promising results are already obtained with our electrodes which do not have skin piercing micro needles. For the proposed electrodes, three different conductive coatings (Ag/AgCl/Au) are compared. AgCl is found to be slightly better than Ag as coating material, while our Au coated electrodes have the highest impedance. I. INTRODUCTION URRENT medical practice uses Ag/AgCl coated electrodes with a conductive gel for ECG/EEG biopotential recordings. The gel improves the signal quality by reducing the equivalent impedance of the electrode-skin interface and by suppressing the stretch-related skin motion artifacts (gel acts as a kind of buffer). Such wet gel electrodes unfortunately have several issues. First, the subject"s comfort is limited by the gel: electrode/gel placement takes time, the wet electrodes are not very comfortable to wear on the skull (in particular on hairy skin) and after electrode removal the (dried) gel needs to be washed away, which is often not easy. Furthermore, smearing of the conductive gel may lead to shorts when electrodes are placed nearby each other. Finally, frequent gel replacement due to gel drying is required to ensure high quality biopotential recording, and allergic skin reactions are possible. Especially for ambulatory monitoring or for ECG/EEG monitoring over long periods of time, such wet gel electrodes are not ideal at all. Dry electrode technology is an interesting alternative. A good review of dry electrodes and their evaluation is Manuscript received April 15, 2011. This work was supported in part by the Agency for Innovation by Science and Technology in Flanders (IWT). F. Vanlerberghe is with imec, Leuven, Belgium and the

2014

The electrocardiogram (ECG) is one of the most important signals acquired from the body, as it serves as the immediate source of information relating to heart performance. Hence, a lot of research has gone into various types of ECG acquisition methods and systems. With the numerous methods and systems available at hand, it is important to compare, contrast, and evaluate the existing techniques. Not only does this help distinguish between the different techniques, it also helps build on the existing methods to create successful acquisition systems that can surpass the effect of unwanted factors, such as movement and other noise artifacts. This paper compares two different ECG acquisition systems, one of which uses PS25015A dry electrodes and the other, which uses two different silver/silver chloride (Ag/AgCl) wet electrodes. ECG signals were acquired from three healthy individuals, in the sitting position, using both systems simultaneously. Signals were first filtered to diminish noi...

Science and Innovation, 2022

Introduction. Active ECG electrodes for daily usable wearable electronics (glasses, headphones) enable making long-term cardiovascular disease diagnostics available to many people.Problem Statement. The methods of ECG recording become more accessible over the years. However, on the way to their general use, even in cases where only reliable registration of the R-wave of the ECG is important, there are certain difficulties associated with the need to apply special electrodes (eg, silver chloride ones) to certain parts of the body through wet pads and to perform specific actions. The problem is solved by using dry electrodes built into the usual devices. However, in this case, a low amplitude of the useful signal and a high contact resistance (for example, on the surface of the head) do not allow recording an ECG by conventional means.Purpose. The purpose of this research is to develop easy-to-use body ECG electrodes that may be built into everyday appliances.Materials and Methods. Ac...

A dry bracelet electrode for electrocardiographic (ECG) signal monitoring was developed and successfully tested in human volunteers. The new electrode dispenses with the usual gel application and the previous skin preparation to monitor the signal. It was fabricated from a polyethylene tereftalate (PET) polymer sheet that was coated with a thin conductive titanium nitride (TiN) layer. As the direct sputtering of the TiN layer on the polymeric surface results in a poor adherence of the layer, a specific polymer activation treatment was developed, consisting of the polymer surface bombardment with alternate beams of argon and titanium ions. The adhesion tests and the SEM analysis of the coatings proved the success of the treatment. The TiN coating displays the fcc crystalline structure of the δ-TiN bulk material with a rough, pyramidal-like morphology. The electrochemical analysis that was carried out in a saline solution (to mimic the skin sweat contact) showed delamination of the film after prolonged contact with the saline solution..