Severe cases of myocardial ischemia can be life-threatening. Whether myocardial ischemia is life-threatening or not depends mainly on the degree and duration of myocardial ischemia. Under normal conditions, myocardial blood supply and myocardial cell demand are in balance with each other, and no uncomfortable symptoms will occur at this time. When myocardial blood supply is impaired or myocardial demand is increased and supply and demand are imbalanced, patients will experience myocardial ischemia, the severity of which is as follows: 1. If it is only mild myocardial ischemia, it can be manifested as insufficient myocardial blood supply after labor or activity, and there will be symptoms of chest suffocation and shortness of breath after activity, then vasodilator drugs or anti-platelet drugs can be given to treat it, and the symptoms of myocardial ischemia will be improved; 2. If the myocardial ischemia is severe, especially in acute coronary syndrome, the sudden appearance of sustained myocardial ischemia will lead to myocardial cell necrosis; even in the early stage of acute myocardial infarction, due to myocardial cell necrosis or electrocardiographic instability, disordered arrhythmia will occur, which often induces cardiogenic shock or sudden death; therefore, this myocardial ischemia is very critical, and you should go to the hospital quickly when you encounter this situation. After timely treatment, the patient will turn to safety.