Motion artifacts in capacitive ECG monitoring systems: a review of existing models and reduction techniques.

Current research focuses on improving electrocardiogram (ECG) monitoring systems to enable real-time and long-term usage, with a specific focus on facilitating remote monitoring of ECG data. This advancement is crucial for improving cardiovascular health by facilitating early detection and management of cardiovascular disease (CVD). To efficiently meet these demands, user-friendly and comfortable ECG sensors that surpass wet electrodes are essential. This has led to increased interest in ECG capacitive electrodes, which facilitate signal detection without requiring gel preparation or direct conductive contact with the body. This feature makes them suitable for wearables or integrated measurement devices. However, ongoing research is essential as the signals they measure often lack sufficient clinical accuracy due to susceptibility to interferences, particularly Motion Artifacts (MAs). While our primary focus is on studying MAs, we also address other limitations crucial for designing a high Signal-to-Noise Ratio (SNR) circuit and effectively mitigating MAs. The literature on the origins and models of MAs in capacitive electrodes is insufficient, which we aim to address alongside discussing mitigation methods. We bring attention to digital signal processing approaches, especially those using reference signals like Electrode-Tissue Impedance (ETI), as highly promising. Finally, we discuss its challenges, proposed solutions, and offer insights into future research directions.

Investigation of Non-contact Electrodes for Electrocardiogram Monitoring.

This work investigates the use of an active noncontact electrode to monitor electrocardiogram (ECG) signals in the chest region of the human body across different interface materials. Non-contact electrodes provide an advantage over wet gel electrodes as they do not require direct contact with the skin which can lead to skin irritation. The key aspects and parameters of non-contact electrodes were discussed. Additionally, a printed circuit board (PCB) electrode was designed and prototyped. Experimental evaluations were performed to demonstrate the feasibility of the design as well as the impact of various interface materials. Results showed that R-peaks can be detected through all materials tested. The highest noise levels were observed in polyester, resulting in the highest signal standard deviation, followed by merino and cotton. The patch sensor with just a solder mask as an insulation layer provided the clearest ECG signal, with 100% accuracy on Rpeak detection.Clinical relevance- Non-contact electrodes offer a more comfortable solution for long-term heart monitoring with minimal discomfort due to less skin irritation when compared to conventional electrodes.