Acute coronary syndrome (ACS) refers to a range of conditions caused by reduced blood flow to the heart. It typically includes unstable angina and myocardial infarction (heart attack). Symptoms may include chest pain, shortness of breath, and discomfort in the arms, back, or jaw. ACS is often a result of coronary artery disease, where arteries become narrowed or blocked. Diagnosis of ACS usually involves electrocardiograms (ECGs) and blood tests to check for heart damage. Treatment may include medications, lifestyle changes, and procedures like angioplasty or stenting to restore blood flow. Early intervention is crucial for better outcomes.