Cardiac Hort is a 24-hour ambulatory ECG monitoring, which is to put electrode sheet on the human body, connect the lead wire and recording box, put on and go home, remove the box after 24 hours, and the computer collects the data in the box to make analysis. 24-hour ambulatory ECG can detect arrhythmias and myocardial ischemia that cannot be detected by conventional body ECG examination. The total number of heart beats for 24 hours is recorded, as well as the number and type of premature beats that occurred during the 24-hour period, and other arrhythmias. A quantitative and qualitative diagnosis of arrhythmia and myocardial ischemia is made, and the cause and nature of syncope and panic can be identified, as well as the efficacy of antiarrhythmic and therapeutic myocardial ischemic drugs and the function of pacemakers can be evaluated.