Acute coronary syndrome (ACS) is a medical emergency that occurs when the blood flow to the heart is suddenly reduced or blocked. Typically caused by plaque build-up in the arteries that supply the heart muscle with oxygen and nutrients, undiagnosed or untreated ACS can rupture or cause a blood clot, leading to a sudden and severe reduction in blood flow to the heart.   ACS can manifest in different ways, depending on the severity and duration of the blockage. The three types of ACS are unstable angina, non-ST elevation myocardial infarction (NSTEMI), and ST-elevation myocardial infarction (STEMI). > Unstable angina...