Noise-Resistant CECG Using Novel Capacitive Electrodes

Abstract

For years, capacitive electrocardiogram (CECG) has been known to be susceptible to ambient interference. In light of this, a novel capacitive electrode was developed as an effective way to reduce the interference effect. This was done by simply introducing the capacitive elector in series with a 1 pF capacitor, and the 60 Hz common mode noise induced by AC power lines was cancelled using a capacitive right leg (CRL) circuit. The proposed electrode did as expected outperform two counterparts in terms of SNR, and particularly gave an up to 99.8% correlation between RRIs extracted from an ECG and a CECG signal, a figure far beyond 52% and 63% using the two counterparts. This capacitive electrode was originally designed for long-term noncontact monitoring of heart rate, and hopefully can be integrated to portable devices for other medical care services in the near future.

Novel Stable Capacitive Electrocardiogram Measurement System

“…The metal plate was moved forward and backward as well as left and right using a motor at different positions to simulate the effect of human-generated moving interference sources on the CECG measurement system. For a full description of the employed interference platform, please consult the previous study of the present research team [33].…”

“…The three main interference sources for CECG measurement are common-mode noise generated by power cords [31], motion artifacts [32], and interference from the external environment [33]. Such interference may cause signal distortion and saturation when measuring physiological signals, minimizing their accuracy.…”

Development and Optimization of Silicon−Dioxide−Coated Capacitive Electrode for Ambulatory ECG Measurement System

“…The capacitive−coupled electrode usually has a dielectric layer on the electrode surface to detect the amount of accumulated charge on the skin surface through the capacitive coupling between the electrode and skin [ 14 , 17 , 18 , 19 ]. The capacitive−coupled ECG approach has several advantages, such as no skin irritation and rash if a biocompatible layer is coated on the electrodes, reusability due to non−adhesive usage, and stable mechanical and electrical properties over time due to the durability of dielectric materials.…”