Portable Multi-sensor System for Digital Processing of Electrocardiographic Signals

Abstract

In the field of medicine and wearable health devices, the need of monitoring the cardiac activity continuously represents a challenge. Electrocardiography is the analysis of cardiac electrical activity, that can be conducted in a clinic with the electrocardiograph. This represents an accurate way to do the analysis, but it is necessary for the patient to go to the clinic, and that can limit the possibility of detecting random cardiac pathological events. In fact, some cardiac pathologies can manifest themselves as non-permanent variations in one or more electrocardiographic leads. As a result, the patient may complain of the symptom but come to the clinic and show a healthy ECG. A portable cardiac monitoring system have to be able to take over on every difference in the acquired cardiac signal from the reference labelled as healthy. Thus, it is essential to ensure that the patient, during the monitoring activity, can carry out daily activities. The aim of this paper is to present a 12-lead ECG portable system based on TI ADS1298. It is an 8 channel, 24 bit analog-to-digital sigma-delta converter. Two ADS1298 connected in daisy-chain mode have been integrated on a single board, in order to be able to acquire from 12 channels (i.e. all 12 cardiac leads). The board communicates with an STM32H743ZI microcontroller. In order to pick up the motion signal, a 6-axis small IMU was integrated in the system, LSM6DSV16X from STMicroelectronics. A threshold mechanism was therefore implemented to allow the acquisition of the ECG signal based on the signal read by the accelerometer.