If a patient suddenly has symptoms of chest tightness, there are usually the following causes: 1. The most common factor is cardiovascular disease, for example, if the patient has a previous history of coronary heart disease, the presence of coronary heart disease, unstable angina pectoris, arrhythmia, myocarditis or pericarditis, valvular disease of the heart, hypertensive heart disease should be considered. Such conditions can lead to ischemic stenosis and spasm of the coronary arteries, causing clinical symptoms of chest tightness; 2. For chronic respiratory diseases, if in acute attacks, there will also be chest tightness due to decreased oxygen saturation and low partial pressure of oxygen, such as chronic bronchitis, asthma, chronic obstructive pulmonary emphysema, chronic pulmonary heart disease, pulmonary hypertension, these conditions will also have the above clinical manifestations; 3. For Some patients with plant nerve dysfunction will also have the above typical symptoms when they have cardiac neurosis.