Feasibility assessment of an optical sensor for long-term electrocardiogram monitoring

Cardiovascular disease is a major risk to human health, which needs long-term monitoring for prevention and early diagnosis. Optical sensors present the advantage of immunity to electromagnetic field and high sensitivity, and have been growing in a variety of emerging medical applications to monitor human cardiac parameters. Most of the current optical sensors can only measure limited cardiovascular information such as the heart rate, therefore, the optics-based approach for cardiac electrophysiology has attracted the attention of more researchers. In this paper, we developed a method to evaluate the availability of our proposed anti-EMI optical sensor. The sensitivity of optical sensor based on electro-optic modulation can achieve 266.4μW/V and detect the electrocardiogram (ECG) by attached to the chest and edge of clavicle. A series of ECG signals over 1 hour were analyzed using proposed method, which is driven by the optimization of R-peak location, Lorenz plot and statistical correlation. ECG monitoring results of the optical sensors are in accordance with a standard clinical device (SOMNOtouch™ RESP) among different subjects. Moreover, both the sensors are tested in daily electromagnetic conditions, and it causes some obvious signal artifacts to the SOMNO system, but almost no effect on the optical sensors during the long-term test. We provide further grounds for such clinical applications by demonstrating, for the first time to our knowledge, optics-based device used in long-term ECG monitoring, an essential tool in modern cardiac monitoring applications.