If patients have been experiencing clinical symptoms and manifestations of chest tightness and shortness of breath in the recent past, the following causes should be considered: First, cardiogenic diseases are considered, such as coronary artery disease unstable angina, or acute myocarditis, acute pericarditis, and infective endocarditis. In addition, if patients have malignant arrhythmias and heart failure, they may also experience frequent chest tightness and shortness of breath, which are related to coronary artery ischemia, stenosis and spasm, or directly related to insufficient blood and oxygen supply to the heart muscle. Secondly, if the patient has chronic pulmonary insufficiency, such as chronic bronchiectasis, chronic emphysema, pulmonary heart disease, pulmonary hypertension, etc., and the arterial oxygen saturation decreases and the partial pressure of oxygen is too low, there will also be frequent chest tightness and shortness of breath. Third, if the patient has obvious hypertension, there is hypertension combined with cardiovascular blood supply deficiency, there will also be chest tightness and shortness of breath. Fourth, if the patient has endocrine metabolic diseases, in the case of thyroid insufficiency, there will also be symptoms of chest tightness and shortness of breath all the time.