Cardiac blood vessel stenosis of 50% may have symptoms of chest pain and chest tightness after activity, and some patients may not have any symptoms. Coronary heart disease diagnostic criteria is a coronary artery and more than one blood vessel stenosis greater than or equal to 50%, coronary heart disease is due to long-term lipid metabolism abnormalities, resulting in lipid deposition in the intima-media of the blood vessels, the formation of plaques. Blockage of coronary arteries, causing ischemia of cardiomyocytes at the distal end of the blocked blood vessels, angina attacks, serious and life-threatening. Cardiac stenosis of more than 50% can cause a decrease in coronary blood supply, the heart’s demand for blood will increase after activity, stenosis will cause a decrease in the heart’s blood supply, when the supply and demand contradictions, can lead to angina attacks. Typical symptoms of angina pectoris are chest pain after activity, some patients have chest tightness as the main manifestation, the pain can radiate to the left upper limb, the pain lasts for about 10~15 minutes, and can be relieved by resting or oral dilation of coronary arteries with drugs such as nitroglycerin. Some patients belong to the hidden type of coronary artery disease, the coronary artery stenosis, but there is no corresponding symptoms of heart ischemia, belongs to a special type of heart disease. Coronary artery stenosis of more than 50% can be diagnosed with coronary artery disease, need to be given under the guidance of a doctor to give regular drug treatment to slow down the progress of the disease, to prevent the recurrence of angina symptoms.