Cardiac ischemia If the myocardial ischemia is relatively short-lived, normal blood perfusion can be restored to the heart muscle cells. However, if the direct cause of myocardial ischemia cannot be removed, only symptoms can be relieved but not cured. Cardiac ischemia refers to the conflict between coronary blood supply and myocardial blood demand due to various reasons, so that the coronary blood flow cannot meet the needs of myocardial metabolism. Causes of reduced myocardial blood supply and oxygen supply or increased myocardial oxygen demand may lead to the occurrence of cardiac ischemia. Mild myocardial ischemia usually manifests as an angina attack. Angina symptoms can be relieved by rest or by taking medications. Medications commonly used in clinical practice to relieve symptoms include mainly beta-blockers, nitrates and calcium channel blockers. When rest or medication is taken, the coronary arteries dilate, blood perfusion is restored, and the patient’s cardiomyocytes can reversibly recover from ischemia and hypoxia. The symptoms of angina can be relieved. Severe myocardial ischemia manifests as acute myocardial infarction. Due to prolonged ischemia and hypoxia, the cardiomyocytes have died and the dead cardiomyocytes cannot be regenerated even if blood perfusion is restored. The most common cause of myocardial ischemia is coronary heart disease, and this cause is difficult to be eliminated by drugs because the coronary arteries are already atherosclerotic and narrowed; the necrotic myocardial cells also cannot be regenerated, and from this point of view, the cause cannot be eliminated and cannot be cured.