A textile integrated long-term ECG monitor with capacitively coupled electrodes

Capacitive EGC sensors are a promising approach for future ECG measurement systems as they do not rely on a moist and direct skin contact. This is especially desirable for long-term monitoring, because capacitively coupled electrodes (CCE) do not cause skin irritations to the patient. In this paper, we present a textile integrated CCE-based ECG monitoring system for long-term application. The system comprises of a convenient garment, active capacitive electrodes as well as a pluggable low-power acquisition unit with Bluetooth telemetry. For this system special electrodes have been developed whose capacitive areas exhibit textile properties. They are completely integrated into the garment and equipped with a textile layer that transports humidity away from the wearer. Additionally, a large breathable reference electrode is used. In the first setup it acts as a conductive grounding when the garment is worn on the skin, and in the second setting it is capacitively coupled, when wearing a shirt beneath. ECG measurements were taken in both settings and qualitative results with the subjects sitting and walking are presented. Particularly, it is pointed out that textile-integrated CCEs in conjunction with a conductive reference electrode is a feasible solution for long-term ECG monitoring in terms of both signal quality and ergonomics.