Devices based on the ECG signal

In this chapter, we discuss issues related to acquiring and processing an electrocardiogram (ECG) signal. The ECG signal is related to the heart's electrical activity and is therefore measured using electrodes. When measuring the ECG signal, we first need to know where to place and how to connect the electrodes. In pervasive computing, mainly two to three electrodes are used, representing a single lead ECG configuration. We briefly introduce how the ECG signal can be generated using simulators, sources of noise and artifacts, and how to assess the quality of the signals. ECG device types and standards are introduced as well. To develop electronics for ECG, we need to know what standards/regulations must be followed and what kind of processing needs to be performed. Therefore, we introduce algorithms for heart rate estimation. We present the ECG front-end in detail and provide information about amplifiers and filters that need to be designed. Some challenges related to designing pervasive ECG devices are presented next. In the end, we discuss how ECG signals can be further processed to estimate heart rate variability.