The danger of angina pectoris is that some cholesterol in the blood, mainly LDL cholesterol, penetrates into the walls of the coronary arteries and builds up to a certain extent, the diameter of the blood vessels will become smaller, affecting the blood supply to the heart muscle. 1, if the angina pectoris blood vessels to take out to cut to see, will find the blood vessel wall accumulation of some like millet porridge like yellow stuff, medical known as “plaque”, plaque accumulation, the coronary artery atherosclerosis occurs. Coronary heart disease myocardial ischemia will make people feel uncomfortable, that is, angina. 2, angina is not as painful as people think, but is often described as a dull ache, burning, choking, squeezing and so on. The typical location is in the middle of the chest, which is behind the sternum, and it can also be on the left or right side of the chest. Some people feel uncomfortable in their left shoulder and left upper limb, while a small number of people have difficulty in moving their jaws, lower teeth or stomach. 3, most of the typical angina occurs during exercise rather than after exercise, stopping exercise or using drugs can make angina relief. However, in older people, angina manifests itself as difficulty in breathing and weakness, and people with diabetes may not feel it at all. 4, the use of previously able to relieve the method can not be relieved, indicating that coronary heart disease into an unstable state, that is, unstable angina. Often due to plaque rupture as well as in the rupture site of the growth of blood clots of different sizes, aggravating the degree of narrowing of blood vessels. 5. The unstable state does not last forever, either returning to stable angina or progressing to the most severe form of myocardial infarction. Doctors are able to determine whether it is unstable angina or myocardial infarction through electrocardiograms and changes in blood cardiac enzymology. 6. The sudden onset of severe myocardial ischemia or myocardial infarction can lead to a slow or fast heartbeat, lowered blood pressure, difficulty breathing, loss of consciousness, and in some cases, sudden death. Severe ones can lead to uncorrectable lowering of blood pressure or cardiac rupture; even if the danger period is passed, angina pectoris or cardiac insufficiency may reoccur.