If a patient has tachycardia accompanied by chest tightness, the following points should be considered: First, endocrine metabolic disorders should be considered first. Often, the above clinical symptoms appear when hyperthyroidism, hyperparathyroidism, or hyperadrenocorticism are present. Secondly, other endocrine diseases, such as diabetes mellitus, may also be manifested. Thirdly, if the patient has cardiogenic diseases, such as unstable angina pectoris, acute myocarditis, acute pericarditis, malignant arrhythmia, or heart failure, the condition may also appear. Fourth, if the patient has cerebrovascular disease, such as acute cerebrovascular accident, cerebral infarction, cerebral hemorrhage, there will also be tachycardia, accompanied by chest tightness and shortness of breath. Fifth, for respiratory system diseases, such as severe lung infection, large pneumothorax, and pleural effusion, the above symptoms will also occur.