Some patients in the outpatient clinic complain of occasional panic discomfort, and the doctor will usually recommend that the patient have an ECG, and the patient will say that he or she has had a lot of general ECGs, and each time they are normal and cannot catch abnormal ECGs, so the clinician will often recommend that the patient bring a 24-hour ambulatory ECG (also known as a “box “(also known as “Holter”). Patients may wonder what the purpose of this little box is. Then we will talk about the ambulatory ECG. I. What is an ECG An ECG is a kind of electrocardiogram that records the electrocardiogram of a patient for a long time, and is an upgrade of the ordinary ECG. Dynamic ECG uses data science technology to collect ECG signals and data in real time, and to quickly analyze and diagnose a large amount of ECG data, so as to discover abnormalities that cannot be found by ordinary ECG. In fact, it simply means that the ECG is done for patients 24 hours a day, and finally summarizes and analyzes it to draw a conclusion report of dynamic ECG. Second, the clinical value of dynamic ECG 1. Monitoring arrhythmia For patients with intermittent episodes of panic, it is not easy to detect because the ordinary ECG time is short and there is no episode of panic symptoms at the time of examination, therefore, checking dynamic ECG can further understand the type of arrhythmia, such as finding the type of slow arrhythmia, the type of rapid arrhythmia, the form, nature and quantity of premature beats, assessing the severity of arrhythmia and To guide the next treatment plan. For patients with clear arrhythmias, antiarrhythmic drugs or pacemakers can be used, and most antiarrhythmic drugs have certain side effects, especially arrhythmogenic effects. 3. Evaluate clinical symptoms When checking the ECG, especially when there are clinical symptoms, record the time and explain the symptoms and time of onset with the ECG physician, so that the physician can evaluate the corresponding relationship between the arrhythmia and the symptoms that appear during life or activity. 4. To find evidence of ischemia Dynamic ECG can detect the presence or absence of abnormal ST-T changes and the degree of changes to assess the degree of myocardial ischemia, and has a high detection rate for myocardial ischemia, as well as localization and diagnosis of the ischemic site and related vessels. 5. Detection of risk factors for syncope or sudden death Dynamic ECG is significant in detecting risk factors for syncope or sudden cardiac death, especially before malignant ventricular arrhythmias that lead to sudden cardiac death, and dynamic ECG can detect ventricular arrhythmias that often have unstable electrical activity, thus helping to take timely and powerful therapeutic measures.