The difference between dynamic ECG and conventional ECG is as follows: 1. Dynamic ECG: It consists of interventional system and playback analysis system, which can obtain ECG information for 24 consecutive hours, or even longer, in the subject’s daily life state, so it can often detect transient abnormal ECG changes that are not easily detected by conventional ECG. Its clinical applications include: (1) determination of the nature of symptoms such as palpitations, shortness of breath, dizziness, syncope and chest pain; (2) qualitative and quantitative diagnosis of arrhythmias; (3) diagnostic assessment of myocardial ischemia, especially an important means to detect asymptomatic myocardial ischemia; (4) evaluation of myocardial ischemia and arrhythmia drug therapy; (5) evaluation of prognosis of heart disease patients. The prognosis of patients after myocardial infarction and other heart disease patients is judged by observing complex arrhythmias and other indicators; (6) selection of indications for pacemaker installation, evaluation of pacemaker function, and detection of pacemaker-related arrhythmias; (7) medical scientific research and epidemiological examination, such as the range of physiological variations of heart rate in normal people, and studies of cardiac function in astronauts, divers, and drivers; 2. Conventional electrocardiogram 2.Conventional ECG: It is recorded by the electrodes on the body surface through the wires that lead to the potential difference generated by the heart excitation process on the body surface, which leads to the ECG tracer.