A Practical Approach concerning the Capacitive Acquisition of the Electrocardiogram in a Moving Wheelchair

Capacitive sensing of the electrocardiogram allows inconspicuous monitoring of the most well-known electrophysiological signal. Wheelchair users with cardiac maladies would benefit from ECG unobtrusive monitoring. However, motion and daily life activities impose strong artifacts to the signal acquired. This study aims at the extended capacitive electrocardiogram acquisition with and without movement. To validate the hardware, and discern on its capability to do long-term monitoring, recordings of 5 minutes were made for immobile and moving wheelchair, and compared with the contact ECG obtained using a reference equipment. Seven subjects tested the immobility scenario, with tight agreement between contact and contactless ECG. Fourteen realistic combinations of inclination and speed were tested on a treadmill, with the capacitive ECG sensing hardware being able to provide comparable results to the reference equipment. Thus longterm capacitive ECG acquisition by means of the hardware setup developed was found feasible and reliable within the test maximum limits of 7 km/h and 4.4% of inclination.