ECG functions to automatically record the biological electrical signals (ECG) generated by cardiac activity when the heart is active, for clinical diagnosis and scientific research commonly used in medical electronic instruments.
Before the heart beats, the myocardium is first excited and produces a weak current in the process of excitation, which is transmitted to all parts of the body. Because the body parts of different tissues, different parts and the distance between the heart, so in the body surface of various parts, showing different potential changes in the human heart of the electrical activity generated by the surface potential and the relationship between time called electrocardiogram. Electrocardiograph is the instrument that records these physiological signals.
In the domestic generally according to the recorder synchronous output number is divided into: single, three road, six road and 12 ECG machine.