The coronary arteries supply blood to the heart muscle itself. Damage to or blockage of a coronary artery can result in injury to the heart. Normally, blood flows through a coronary artery unimpeded. However, if the inner wall of a coronary artery becomes damaged, cholesterol plaque can build-up, progressively narrowing the available pathway through which blood can flow.

Clotted blood attempting to traverse the blood vessel may find it tortuous and too narrow for passage, and the artery may become completely constricted or blocked-off. The blocked artery results in a lack of oxygen, or ischemia, to the part of the heart muscle that the artery supplies. The result is a heart attack.