Chest pain refers to pain between the neck and the lower edge of the thorax, and the nature of the pain can be various, mainly seen in lesions of the chest wall, pleura, lung, cardiovascular, mediastinum, esophagus, diaphragm, intercostal nerve, and other parts. Chest pain is a common clinical symptom, and the nature of pain can become various, so the performance of chest pain of related diseases also varies. Cardiovascular system: 1. Acute myocardial infarction: (1) the patient has the basis of coronary artery lesions, high-risk factors, occurs 20-30 minutes after the acute coronary occlusion, is a persistent severe pain behind the sternum, containing “nitroglycerin tablets” can not be relieved, the patient is more irritable, hypotensive shock, etc.; (2) signs: tachycardia, can (2) physical signs: tachycardia, reduced first heart sound, cyanosis, gallop rhythm, low blood pressure except for the early increase in blood pressure, almost all low blood pressure (3) auxiliary examination: characteristic ECG progressive changes: the S-T segment in the leads of the necrotic area of the face has an arch-back upward type, the T wave is inverted, in the leads of the dorsal myocardial necrosis area appears the opposite change, the patient before and after admission to the hospital ECG consistent. (4) Myocardial injury markers myoglobin, CK-MB, and troponin T and I were elevated. 2, angina pectoris: the pain site is similar to myocardial infarction, but lighter in nature, shorter in duration, mostly not accompanied by arrhythmia, heart failure or (and) shock, and can be relieved by nitroglycerin. There are ST-T changes in the ECG, but there is no dynamic evolution of myocardial infarction. Laboratory tests show that myocardial necrosis markers (myoglobin, troponin I or T, CK-MB, etc.) are generally not increased. 3, acute pericarditis: especially acute non-specific pericarditis may also have severe and persistent chest pain and ST-segment elevation. However, the chest pain is aggravated by the presence of fever, breathing and coughing at the same time. Pericardial friction sounds may be heard in the early stages. The electrocardiographic changes are usually a generalized ST-segment elevation in leads with no evolution of the AMI electrocardiogram and no serum enzymatic changes. Echocardiography can confirm the presence or absence of pericardial effusion and determine the amount of effusion. Cardiac magnetic resonance imaging can help to distinguish the nature of effusion, and can measure the thickness of the pericardium, which is more sensitive to the diagnosis of pericarditis. 4, aortic coarctation: (1) Patients are often men around 60 years old, 90% with a history of hypertension and sudden onset of severe chest and back pain. (2) The site of chest pain is quite similar to acute myocardial infarction, and the sudden chest pain starts to reach its peak, which is tear-like or knife-like pain and can radiate to the back, scapula, abdomen, etc.; (3) physical examination: inconsistent pulse or blood pressure in both upper limbs. (4) Ancillary examinations: echocardiography probes the fluid in the layers and shows double lumen images of the aorta. CTA tomography can be observed to divide the aorta into true and false lumens and is the most commonly used method of preoperative imaging evaluation. Aortic digital silhouette angiography DSA is the “gold standard” for the diagnosis of aortic coarctation. Other cardiovascular diseases that may present with chest pain: cardiomyopathy, cardiac neurosis, sick sinus syndrome, heart valve lesions, etc. Respiratory system Acute pulmonary embolism: (1) Patients mostly have a history of fracture, surgery or long-term bed rest. (2) Sudden onset of unexplained chest pain, hemoptysis, dyspnea “triad”, chest pain is mostly confined to the affected area, accompanied by a sudden increase in respiratory rate, agitation, syncope, shock or cardiac arrest, etc.; (3) Wet rales can be heard in the base of both lungs, tachycardia, blood pressure changes, abnormal jugular venous filling, P2 in the pulmonary valve area hyperactivity, swelling of both lower extremities; (4) auxiliary examinations: ECG: sinus tachycardia, S wave in lead I, Q wave in lead III, right deviation of electrical axis, pulmonary P wave, etc. Blood gas analysis with hypoxemia. D-dimer <500μg/L can exclude PE . There is usually no myocardial enzymatic changes. Cardiac ultrasound: findings of right heart overload, reduced ventricular wall motion, signs of pulmonary hypertension, and hemodynamic changes are highly suspicious of PE. Spiral CT is the most commonly used tool for the diagnosis of pulmonary embolism: direct visualization of the thrombus in the pulmonary artery, the "orbital sign" of a low-density filling defect in the vessel, or a complete filling defect, with no visualization of the distal vessels. No visualization. Pulmonary arteriography is the gold standard for the diagnosis of PE, with complete obstruction or filling defect of the pulmonary artery, slow flow of contrast, and local hypoperfusion. Other respiratory diseases that can present with chest pain: pneumonia, tuberculosis, lung abscess, spontaneous pneumothorax, acute pleurisy, diaphragmatic hernia, etc. Digestive system Gastroduodenal ulcer perforation, acute pancreatitis, acute cholecystitis, cholelithiasis. Signs of typical acute abdomen are often present, and electrocardiogram and enzymatic examination assist in identification. Chest wall lesions such as trauma to the chest wall, bacterial infections, viral infections, tumors and other local skin, muscle, bone and nerve lesions. Commonly, acute dermatitis, subcutaneous cellulitis, herpes zoster, painful obesity, myositis and dermatomyositis, epidemic myalgia, cervical spine pain, costochondritis, bone tumors, intercostal neuritis, radicular pain, etc. Among the common features: 1, the site of pain is fixed at the lesion, and there is obvious local pressure pain; 2, deep breathing, coughing, raising the arm, bending and other movements make the pain of thoracic activities increase. Other diseases Such as leukemia, related mediastinal tumors, etc.