Coronary artery spasm is a pathophysiologic condition that is usually transient, returns to normal quickly, and lasts mostly from a few minutes to tens of minutes, usually no more than half an hour. Coronary artery spasm (CAS) is a condition in which the smooth muscle of the inner wall of the arteries of the heart narrows or occludes the lumen of the blood vessels due to the action of triggers such as smoking or drinking, and usually returns to normal very quickly, and therefore lasts for a few minutes to dozens of minutes in most cases. If the coronary artery itself is diseased, such as endothelial cell dysfunction, the duration of coronary artery spasm will be prolonged. Depending on the location and severity of the coronary spasm and whether or not collateral circulation is established, different types of clinical manifestations may occur. Coronary spasm lasting several minutes to tens of minutes may induce angina pectoris, which can be relieved by sublingual nitroglycerin as prescribed by the physician. If it lasts for more than half an hour, myocardial infarction caused by myocardial ischemia is considered, and prompt medical attention is needed to avoid delaying the condition.