Coronary heart disease is the most common disease of the cardiovascular system, which seriously affects the quality of life and life expectancy of patients, but some patients do not have coronary heart disease. Coronary heart disease classification: asymptomatic myocardial ischemia; angina pectoris; myocardial infarction; ischemic cardiomyopathy; sudden death. Prevalent population: 1, with a history of smoking, diabetes, hypertension, hyperlipidemia, etc. 2, mostly middle-aged and elderly. 3, symptoms: mostly boring pain, atypical can be chest tightness, shortness of breath. 4.Location: mostly in the posterior sternum and precordial area, atypically in the neck or even teeth, and may be discharged to the back of the shoulder. 5, triggers: mostly after activity, but sudden onset of myocardial infarction. 6.Mode of relief: rest or taking anti-cardiac pain, nitroglycerin, etc. 7, duration: several minutes, such as a few seconds is generally not, such as a particularly long time, greater than 30 minutes, except for myocardial infarction also temporarily disregarded. Many patients with cardiovascular neurosis have cardiac discomfort, most poor sleep, mental anxiety, the onset of no cause, the duration of more long or a few seconds, containing nitroglycerin relief is not obvious, accompanied by sweating, limb tremors, abdominal discomfort, dizziness, etc., such patients have no abnormal examination.