Investigating Structural and Positional Impact on ECG Signal Quality of Knitted Active Electrodes for Real Time Healthcare Monitoring

Heart disease is the leading cause of death globally, often going undetected without hospital intervention. Wearable heart rate monitoring (ECG) devices are essential to reduce this problem and provide an efficient and user-friendly means of monitoring the wearer throughout their daily life. This paper investigated the impact on the position and fabrication structure of these wearable electrodes on the electrical quality of the ECG signal. The electrodes were fabricated using a 12-gauge Shima Seiki SES122-S flatbed knitting machine and combined with flexible miniaturised buffer amplifier circuits linked with the electrode to create ‘active’ electrodes that help improve the signal to noise ratio (SNR). Three placement positions for the electrodes were investigated (2 chest positions (horizontal and vertical) and 1 waist) and the position of the amplifier relative to the electrodes (1, 10, 20 cm) was adjusted to identify the optimum SNR representing the effect of electronics positioning relative to the electrodes. The vertical chest position provided the optimal SNR (21.27 dB), a factor of 4 improvement compared to previous results.