An Unconstrained Cardiac Monitoring System With Novel Dual Tripolar Concentric Ring Geometry-Based Flexible Active ECG Electrodes for Sleep Health Surveillance

In this paper, an unconstrained cardiac monitoring system with a novel dual tripolar concentric ring (D-TCR) geometry-based flexible active ECG electrodes is presented. The D-TCR ECG electrode, which based on the conductive flexible and stretchable Ag NWs/PDMS composite material, is designed to acquire the high-fidelity electrocardiographic potentials. The proposed system overcomes the constraints of the conventional ECG monitoring device, and provide the superiorities in far-field rejection, power line interference attenuation, driven right leg-release, etc. The effectiveness and feasibility of the proposed system were evaluated on a dataset that involves 16 subjects with different clothing materials and sleep postures. The average Pearson correlation coefficient of the heart rate variability (HRV) that extracted from the ECG signals obtained by the proposed system and the commercial device can reach over 0.95 with different clothes and postures. Furthermore, to give the quantitative analysis of the ECG, the error rates of time-domain and frequency-domain features extracted from the ECG signal are measured, which are less than 3%. Experimental results exhibit that the proposed system can achieve favorable signal quality and satisfy the basic requirements of the cardiorespiratory monitoring during sleep. Furthermore, the proposed system is expected to provide valuable information for sleep health surveillance, e.g., detecting cardiac abnormalities.