Wireless CardioS framework for continuous ECG acquisition

Abstract

A first-level textile-based electrocardiogram (ECG) monitoring system referred to as “CardioS” (cardiac sensor) for continuous health monitoring applications is proposed in this study to address the demand for resource-constrained environments. and the signal quality assessment of a wireless CardioS was studied. The CardioS consists of a Lead-I ECG signal recorded wirelessly using silver-plated nylon woven (Ag-NyW) dry textile electrodes to compare the results of wired wearable Ag-NyW textile electrode-based ECG acquisition system and CardioS. The effect of prolonged usage of Ag-NyW dry electrodes on electrode impedance was tested in the current work. In addition, electrode half-cell potential was measured to validate the range of Ag-NyW dry electrodes for ECG signal acquisition. Further, the quality of signals recorded by the proposed wireless CardioS framework was evaluated and compared with clinical disposable (Ag–AgCl Gel) electrodes. The signal quality was assessed in terms of mean magnitude coherence spectra, signal cross-correlation, signal-to-noise-band ratio (S_band/N_band), crest factor, low and high band powers and power spectral density. The experimental results showed that the impedance was increased by 2.5–54.6% after six weeks of continuous usage. This increased impedance was less than 1 MΩ/cm², as reported in the literature. The half-cell potential of the Ag-NyW textile electrode obtained was 80 mV, sufficient to acquire the ECG signal from the human body. All the fidelity parameters measured by Ag-NyW textile electrodes were correlated with standard disposable electrodes. The cardiologists validated all the measurements and confirmed that the proposed framework exhibited good performance for ECG signal acquisition from the five healthy subjects. As a result of its low-cost architecture, the proposed CardioS framework can be used in resource-constrained environments for ECG monitoring.

Keywords:

• Cardiac sensor (CardioS)
• silver-plated nylon woven (Ag-NyW) textile electrode
• signal quality
• skin-electrode impedance variation
• half-cell potential

Ethical approval

The ethical guidelines of the institutional and/or national research committee, the 1964 Helsinki statement and its later amendments, or comparable ethical standards were followed in all procedures carried out in studies involving human participants. Before recording the volunteers’ vital signs, an informed consent form was taken from each volunteer.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The Department of Biotechnology (DBT), India provided funding for the completion of this research project (BT/PR14751/MED/32/422/2015), which the authors gratefully acknowledge.