The actual number of days of hospitalization depends on the specific condition and the specific test results. If it is only a simple cardiography, it is even possible to be discharged on the same day. After hospitalization for cardiac angiography, the treatment process is as follows: routine preoperative tests, such as blood tests, chest radiographs, etc., except for contraindications. If there are no contraindications a cardiac angiogram will be scheduled. If the angiogram results are normal and there are no serious complications, the patient can be discharged on the same day. However, if the angiogram reveals a more severe stenosis in the vessel, a stent needs to be placed intraoperatively and postoperative antiplatelet medication needs to be applied. 2-3 days of observation is usually required to observe for acute in-stent thrombosis and other complications. Pre-operative cardiac angiography-related examinations are indispensable. Once the examination reveals abnormal indicators, the original disease may have to be treated first before cardiac angiography is performed.