The introduction of electrocardiogram is very simple. Just look at the common electrocardiogram and combine other people's suggestions and some textbooks. However, it is very difficult to improve after introduction. It is necessary to look at the problem in combination with clinical manifestations and pre-illness. Guided ECG is enough for routine medical treatment, but it needs to be improved for people who want to engage in complex cardiac activities such as electrophysiology. Having said that, I just want to say that every exam has its place, and there are other exams that can't be replaced. Without clinical experience, it is too difficult to learn ECG.