The 24-hour ambulatory ECG results are mainly used to detect arrhythmias and myocardial ischemia, especially for the diagnosis of arrhythmias, to detect occult arrhythmias, to understand the duration, frequency, occurrence and termination patterns of arrhythmias, and to assist in the selection of antiarrhythmic drugs, to adjust the dose or to consider other treatments. The timing of the onset of the patient’s symptoms and the ambulatory ECG are combined to determine whether the symptoms are heart-related and can also be used to determine pacemaker function. The main reason for doing such a long test is to capture the changes in the ECG when there are symptoms. Simply enter the time on the computer and the ECG at that time will be immediately pulled up and an accurate judgment can be made, such as arrhythmia or myocardial ischemia.