What is an ECG? How does it help in the field of medicine?

Explanation

The electrocardiogram (ECG) is one of the simplest and oldest cardiac investigations available. In ECG, the sound variations produced by heart is converted into electric signals. Thus an ECG is simply a representation of the electrical activity of the heart muscle as it changes with time. Usually it is printed on paper for easy analysis. The sum of this electrical activity, when amplified and recorded for just a few seconds is known as an ECG.