Coronary arteries are the blood vessels that supply the heart. Acute Coronary Syndrome (ACS) is the term used to describe three types of coronary artery disease associated with sudden plaque rupture within the coronary artery:
- Unstable angina
- Non-ST segment elevation myocardial infarction (NSTEMI)
- ST segment elevation myocardial infarction (STEMI)
The location of the blockage, the duration of blocked blood flow, and the extent of damage determine the type of acute coronary syndrome. These life-threatening conditions require immediate medical care.
Unstable Angina
Unstable angina is the addition of new symptoms or a change in the characteristics of existing stable angina (chest pain). It may include more frequent episodes of angina, angina occurring at rest more easily, more severe pain, or prolonged episodes. While this type of angina can often be relieved with oral medications, it is unstable and can progress to a heart attack. Typically, more intensive medical treatment or procedures are required. Unstable angina is an acute coronary syndrome and requires URGENT treatment.
Heart Attack: Non-ST Segment Elevation Myocardial Infarction (NSTEMI)
This type of heart attack (MI) may not show changes on an electrocardiogram (EKG). However, elevated levels of chemical markers in the blood indicate damage to the heart muscle. In NSTEMI, the blockage may be partial or temporary, and therefore, the extent of damage is relatively small.
Heart Attack: ST Segment Elevation Myocardial Infarction (STEMI)
This type of heart attack (MI) occurs due to the sudden and prolonged cessation of blood flow caused by the blockage. It affects a large area of the heart muscle, resulting in significant changes on the EKG and elevated levels of chemical markers in the blood.

