1558-1748 (c) 2019 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/JSEN.2019.2946058, IEEE Sensors Journal Performance Evaluation of Woven Conductive Dry Textile Electrodes for Continuous ECG Signals Acquisition Rama Reddy R, Student Member, IEEE, Natarajan Sriraam, Senior Member, IEEE, Prabhu Ravikala Vittal, Member IEEE and Uma Arun Abstract— Electrocardiogram (ECG) signal monitoring is one of the essential techniques for determining the physiological state of human beings. Long-term ECG monitoring is very much essential for the diagnosis and treatment of infrequent arrhythmic episodes. Although, most of the wearable microelectronic ECG implementations employ the well- established surface electrodes technology for bio-potential recordings; they are found to be susceptible to skin irritation and influence the skin-contact impedance to larger extent in long- term monitoring applications. Integration of such sensors into wearable intelligent biomedical clothing is not feasible. This specific research study determines the application of two different conductive textile fabric materials, namely, the woven conductive silver and conductive knitted jersey as dry textile electrodes for ECG biopotential acquisition. The skin-electrode contact impedance measurements for both electrodes presented reduced skin-contact impedance of less than 1 MΩ/cm 2 compared to 1-5 MΩ/cm 2 as reported in literature. The performance of the proposed textile sensors is evaluated qualitatively through visual inspection and quantitatively using metrics such as power spectral density, kurtosis, baseline wander analysis, and signal- to-noise ratio (SNR). The obtained quantitative measures were compared with standard clinical grade conductive-gel based disposable Ag/AgCl surface electrodes. The simulation and comparison studies showed that, the proposed textile electrodes exhibit acceptable performance for ECG acquisition and in some instances improved performance than the traditional commercial disposable gel-based surface electrodes. Index Terms - ECG Monitoring; conductive fabric; textile electrodes; skin-contact impedance I. INTRODUCTION Wearable monitoring of physiological parameters is gaining importance due to the demand for the predictive and progressive healthcare by the patient population [1]. Further, adding to this, there is an increasing demand for the intelligent biomedical clothing, smart garments in the field of sports medicine and ambulatory cardiac disease monitoring [1], [2]. The authors are with the Center for Medical Electronics and Computing, M.S. Ramaiah Institute of Technology, Bangalore, India. (E-mail:sriraam@msrit.edu ; rreddy@ieee.org ). This work was supported by the Department of Biotechnology (DBT), India, under the task force on bioengineering initiative; BT/PR14751/MED/32/422/2015). Acquiring long duration, unobtrusive and artifact-free bio- potentials using wearable systems is very much essential for detection of irregular, infrequent pathognomonic episodes of different arrhythmias [1], [2]. The 'Continuum of care' concept requires the availability of intelligent, comfortable and simple to use devices for unobtrusive remote monitoring. Besides, it is essential that these systems should set the patient's free from cumbersome wires and manual placement of conventional gel- based sensors on the body to avoid discomfort to the patient during daily activities [1]-[3]. For the biomedical research community, designing wearable systems for continuous physiological signal monitoring poses a great challenge. Wearable microelectronic systems like ActiWave Cardio by CamNtech, or ZIO patch by iRhythm Technologies, or Bionomadix by Biopac, or CardioLeaf by Clearbridge use the conventional disposable electrodes for long duration ECG acquisition. In addition, most of the ECG monitoring devices deployed in clinical environments rely on traditional pre-gelled Ag/AgCl electrodes for acquiring cardiac potentials. These electrodes cause discomfort and skin rashes during long-term recordings. Moreover, drying up of gel cause increase in skin- electrode-contact impedance, leading to more sensitive behavior towards artifacts and power-line noise [3]. To overcome the limitations posed by conventional Ag/AgCl electrodes and to embed textile electrodes in intelligent-smart clothing, new approaches towards designing textile electrodes is the need of the hour. The application of dry electrodes in ambulatory ECG recordings [3] was proved to be effective with reduced skin- contact impedance and thereby reduction in motion artifacts [4]. Furthermore, the researchers studied different polymeric foams alongside conductive materials [4], because of its flexibility, body surface geometric conformity, and cushioning effect. Different types of electrode conductor materials were employed [5] and tested for their suitability in developing biopotential recording electrodes. The less conductive or non- conductive substrate materials with conductive metal yarns or coatings weaved or knitted as conductive textiles or fabrics were also explored with different metal compositions and combinations to develop biopotential recording electrodes [5]. The knitted or conductive silver coated fabrics prove to be useful in recording biopotential [5], [6]. Further, few studies proposed screen printed [7] and dry-non- contact [8] electrodes which needs further research to prove