A 72-year-old man named Yan woke up in the morning with a sudden feeling of chest tightness and discomfort, and immediately went to a nearby community health center. At that time, no abnormalities were found in the electrocardiogram and blood tests, so the doctor asked him to stay in the hospital for observation, monitoring the electrocardiogram and reviewing the indicators of myocardial injury. Feeling that the doctor was making a big deal out of it, Yan sneaked out of the hospital and suddenly collapsed while crossing the street! A passerby who noticed Yan’s condition called 120, and when the ambulance arrived, the doctor extubated him and defibrillated him on the way to the hospital. When he was sent to the emergency department of our hospital, Yan’s consciousness and spontaneous respiration had not recovered, and his electrocardiogram indicated extensive anterior wall myocardial infarction. Under ventilator-assisted ventilation and hypothermia, stenting was performed to open the occluded anterior descending branch, and Yan finally regained consciousness and spontaneous respiration 4 days later. Clinically, many patients rush to the hospital when they notice symptoms, but some may have no abnormalities on examination at that time, thus neglecting or refusing to stay in the hospital for observation, resulting in danger outside the hospital. This case reminds us of the following two points: First, the development of acute infarction is a dynamic process, in the earliest stage of the disease, the ECG may not show obvious abnormalities, and blood tests for markers of myocardial injury are not elevated, so the doctor suspects that it is an infarction, he or she will ask the patient to stay in the hospital for observation, and then do the ECG and blood tests after a certain interval of time. In this case, the patient should fully trust the doctor and actively cooperate with the treatment. Secondly, one should not take a chance. In China, sudden death from heart attack accounts for more than 70% of out-of-hospital cases, and the chance of successful resuscitation is low, so it is unlikely that everyone will be as lucky as Mr. Yan. In contrast, the success rate of sudden death in hospitals is relatively high, because doctors and nurses are more specialized in CPR and can also perform other resuscitation. At present, the level of CPR in public places in China is far from that of developed countries in Europe and the United States. It is necessary to improve the level of public CPR.