Acute coronary syndrome (ACS) is a term used to describe a range of conditions associated with sudden, reduced blood flow to the heart. This can lead to a heart attack (myocardial infarction) or unstable angina, which is chest pain or discomfort that occurs at rest or with exertion. ACS is usually caused by a buildup of plaque in the coronary arteries, which supply blood to the heart muscle. When a plaque ruptures, a blood clot can form, partially or completely blocking the flow of blood to the heart muscle. Symptoms of ACS can include chest pain or discomfort, shortness of breath, nausea, and sweating. Treatment for ACS typically involves medications to reduce clotting and improve blood flow, as well as procedures such as angioplasty or bypass surgery to restore blood flow to the heart. Early diagnosis and treatment of ACS are crucial to prevent further damage to the heart muscle and improve outcomes for patients.