Normal ECG examination requires patient preparation as well as examiner preparation. 1. Patient preparation: patients should dress loosely, should not be too hungry or too full, and avoid smoking and alcohol. During the examination, lie flat on the examination bed, fully expose the chest, wrists and ankles, put your hands flat on both sides of your body naturally, take a deep breath to make your whole body muscles and spirit relax, don’t talk and don’t move around. If you are taking heart medication, please explain to your doctor in advance. 2. Examiner’s preparation: the examiner should apply water or alcohol to the electrode sheet area to reduce the resistance of skin conductivity, and then accurately place the limb lead and chest lead on the corresponding position of the skin, start and observe the waveform of the ECG, and then start recording and printing after the waveform is stable. ECG is only a routine examination and there are many factors affecting it. If the examination shows an abnormal ECG, it is necessary to combine with other examinations to make a comprehensive judgment, and there is no need to be overly nervous. If there is any discomfort, consult a doctor promptly.