In summary, the ECG has progressed a long way since it was developed in the early 1900s. The ECG market can be divided into three segments based on complexity; low-end, mid-end and high-end. As the instruments increase in sophistication the number of sensor leads also increases, creating the need for more complex analog circuitry, MCUs, signal processing and power circuitry. The basic building blocks of the modern ECG include an analog front end, instrumentation amp, high and low pass filters, gain amplifiers and an ADC which communicates with the MCU. Power management is also a major concern in these systems that require stable, noise free power, frequently on multiple rails, for the application.