24-hour ambulatory electrocardiogram (ECG) is a test to check whether a patient has arrhythmia, myocardial ischemia and other diseases, which helps to accurately assess the patient’s condition and prognosis. 24-hour ambulatory electrocardiogram can obtain 24-hour electrocardiogram data under the subject’s daily life state, and can detect transient abnormal electrocardiogram changes that are not easy to be detected by conventional electrocardiogram. It is commonly used in clinical practice to assess the presence of arrhythmia, myocardial ischemia and other diseases, which helps to accurately assess the patient’s condition. In addition, 24-hour ambulatory electrocardiogram can also be used for prognostic evaluation of heart disease patients, for example, it can be used to determine the prognosis of patients with myocardial infarction. 24-hour ambulatory electrocardiogram should be performed under the guidance of a specialized physician, and the patient should actively cooperate with the activities of the testing process and the recording of symptoms.