Cardiac monitoring with a smart textile based on polymer-encapsulated FBG: Influence of sensor positioning

In recent years, wearables are exploding in popularity as unobtrusive devices able to extend traditional healthcare delivery systems. Smart textiles are one of the main innovative types of wearables used for non-invasive and continuous monitoring of cardiac activity. A prominent solution is based on the detection of vibrations induced on the chest surface by the heart beating (i.e., precordial motions). In the literature, different sensor positions have been investigated, but it appears to be a lack of accepted standard points for the detection of heart-induced motions. In this work, a smart textile based on fiber Bragg grating (FBG) sensor has been proposed to detect the precordial motions on the chest. The feasibility of the smart textile for cardiac monitoring has been evaluated on three volunteers at three measurement points. Then, the influence of the measurement site on the response of the smart textile has been preliminarily assessed in terms of peak-to-peak amplitude of the signal. The signal amplitude is greater than the noise, so it allows detecting precordial motions. These promising results foster future investigations on the capability and performance of the system in estimating heart rate. Further tests will also be devoted to finding out the optimal measurement points to standardize the sensors positioning in this specific application.