Unstable angina is a type of chest pain or discomfort caused by a sudden reduction in blood flow to the myocardium, often due to a rupture of an atherosclerotic plaque in the coronary arteries
Unlike stable angina, which occurs predictably during exertion, unstable angina can occur unexpectedly, even at rest, and typically lasts longer
It is considered a medical emergency and is often a warning sign of an impending myocardial infarction