Why is angina easily misdiagnosed? The main reason for this is that only an electrocardiogram performed during or just after an attack of angina can show characteristic changes, and this opportunity is not easily touched. Therefore, it is difficult to diagnose angina pectoris exclusively on the basis of medical devices. To carry out self-diagnosis, it is usually necessary to recognize and grasp several distinctive features of angina pectoris: 1, the site of the disease: the main site of angina pectoris pain is in the upper and middle part of the sternum after the pain is about the size of a fist or more than a fist, and sometimes it can be a little to the left or more extensive and involves most of the precordial area. 2, the pain often radiates to the left upper limb: this is an important feature of angina pectoris. Most of the pain is from the left shoulder along the left arm in front of the medial forearm through the forearm to reach the little finger and ring finger, and sometimes also radiates to the neck, pharynx and lower jaw and teeth. 3, the nature of pain: angina pectoris is not a severe colic, but more often manifested with a feeling of pressure or constriction, a persistent dull pain, rather than pinprick-like or throbbing. Often accompanied by a feeling of suffocation, sometimes there will be a sense of fear of dying, forcing the patient to immediately stop the action, unwilling to move or even afraid to speak. 4, the trigger of the attack: angina pectoris is often induced under certain conditions, the most common of which is physical labor, followed by emotional excitement, cold, satiety and so on. It should be noted that the attack is at the time of labor or intense activity, not after stopping labor or activity, and often disappears soon after stopping labor or activity. Emotional excitement, including worry, anxiety, anger, rage, or over-excitement, can be a separate trigger for an attack. 5, the duration of the attack and mitigating factors: general angina attack time is mostly within 5 minutes, rarely more than 10 minutes, after resting or removing the cause of rapid cessation. When the attack, sublingual nitroglycerin can often make the pain disappear within 2-5 minutes. Anyone who basically meets the above five items or fully meets four of them can be initially identified as angina pectoris. At this point, you should go to the hospital to further check the blood lipids, or do ECG load test, and then combined with the patient’s age and family history, blood pressure and other conditions, to make a definitive diagnosis. Prevention of angina attacks should eliminate the triggering factors, patients should summarize the characteristics of each attack according to the specific situation of the individual, adjust the amount of physical activity, avoid excessive emotional excitement, anxiety, anger, mental tension, reduce unnecessary psychological burden.