Causes
Every organ needs oxygen-carrying blood to stay alive, and the myocardium,
the muscle that forms the wall of the heart, is no exception. It has its
own oxygen supply, via the coronary arteries. In coronary artery disease, fatty
deposits (plaques) form in the inner walls of the coronary arteries,
narrowing them and reducing blood flow to the heart. This process is called
atherosclerosis.
Most heart attacks occur when the lining of an artery ruptures and the atherosclerotic
plaque is exposed. Blood then forms a clot on the damaged artery which may partially
or completely obstruct blood flow. If the blockage gets severe enough, heart
attack symptoms appear, and heart muscle cells may start to die, this is now
considered a heart attack.
Rarely, a coronary artery spasm stops blood flow through an apparently healthy
coronary artery, causing a heart attack. Most of the time there's no identifiable
cause.