ECG processing or monitoring system is a software program that receives a cardiological signal at the input and, through a complex mathematical analysis of the data array, produces a result in the usual form for a doctor in the form of a set of indicators that characterize the work of the heart. The basis of such software are digital signal processing (DSP) algorithms, applied statistical analysis algorithms, multi-dimensional classification algorithms. ECG algorithms must meet certain requirements in order to be safe for patients and useful for physicians. Such algorithms must provide the required performance (accuracy) and are subject to mandatory regulatory processes.. These algorithms must be sufficiently robust with respect to the quality of the input signal, since the ECG signal is characterized by a significant noise level in a wide frequency range. This problem is usually solved with complex digital filtering systems. As a result, an ECG algorithm typically produces annotation of heart beats (including the positions of PQRST waves and their amplitudes, types of heart beats), heart rate, interval measurements, and rhythm events interpretation.

Processing of the ECG signal can be complicated by various factors, such as:

• Noises
  The ECG signal can be contaminated by various noises, such as: power line noise, electromagnetic interference, patient movements, and other artifacts. Noise can make it difficult to accurately determine the shape and characteristics of the ECG signal.

• Artifacts
  Artifacts such as muscle movements, respiratory muscle spasms, patient body movements and other similar factors can also complicate the processing of the ECG signal.

• Individual differences
  the ECG signal may vary depending on individual differences in the shape of the heart, its location in the chest, and other factors.

• Poor ECG recording quality
  Poor ECG recording quality, which can be caused by incorrect electrode placement, poor electrode quality, insufficient contact between the electrodes and the skin, can also complicate the processing of the ECG signal.

In general, accurate processing of an ECG signal can be a challenge due to a variety of factors, but with the use of appropriate signal processing and analysis techniques, many of these problems can be solved.