According to the etiology, the types of syncope are mainly divided into four categories: autonomic-mediated reflex syncope, upright intolerance syndrome, cardiogenic syncope, and syncope due to other causes, as follows: 1, autonomic-mediated syncope 1, vasovagal syncope: Mostly stimulated by emotion and pain, the vagus nerve excitation is generated by nerve reflexes, resulting in extensive peripheral small-vessel dilation, slowed heart rate, decreased blood pressure, decreased cerebral blood flow and syncope. Contextual syncope: related to specific actions, commonly coughing syncope, urinary syncope, defecation syncope and swallowing syncope, also seen after exercise, laughing, etc.; 3. Carotid sinus syndrome: due to compression of carotid sinus, mostly seen in elderly men, caused by compression of carotid sinus with hands, sudden neck turn, tight collar, local tumor, shaving, etc. Carotid artery compression, causing syncopal episodes; 4. Atypical reflex syncope: often no trigger or antecedent factors, no clear trigger, positive results on tilt test, no organic heart disease. Second, upright intolerance syndrome Syncope caused by upright hypotension and postural tachycardia syndrome (POTS). Upright hypotension is mainly caused by drugs (diuretics, vasodilators, isoproterenol, etc.), hypovolemia, and impaired autonomic function, and postural tachycardia syndrome can be caused by prolonged standing or bed rest. Third, cardiogenic syncope 1, arrhythmogenic syncope: arrhythmia causes hemodynamic disorders, resulting in a significant decrease in cardiac output and cerebral blood flow, including abnormal sinus node function, supraventricular tachycardia, long QT syndrome, etc.; 2, organic cardiovascular disease combined with syncope: when the demand for blood circulation exceeds the compensatory capacity of the heart and cardiac output cannot be increased accordingly, patients with organic cardiovascular disease will experience syncope, such as acute Myocardial infarction, atrial mucinous aneurysm, severe aortic stenosis, pulmonary embolism, acute aortic coarctation, pericardial disease, etc. IV. Other causes Brain lesions such as vertebrobasilar artery ischemia, basilar artery-type migraine, and subclavian artery steal syndrome can affect posterior circulation blood supply and lead to syncope.