Myocardial ischemia is a state of ischemia and hypoxia in the heart muscle and myocardial cells caused by various reasons, and myocardial ischemia is divided into symptomatic myocardial ischemia and asymptomatic myocardial ischemia. Symptomatic myocardial ischemia, usually referred to as the appearance of chest tightness, chest pain, panic, shortness of breath symptoms; asymptomatic myocardial ischemia is no obvious symptoms, mostly because the state of myocardial ischemia is found by doing electrocardiogram, resulting in myocardial ischemia for many reasons, commonly hypertension, diabetes, hyperlipidemia, obesity. In addition, atherosclerosis also occurs with age, and atherosclerosis can also lead to myocardial ischemia and hypoxia. Myocardial ischemia is due to myocardial infarction, which is an infarction of the coronary arteries.