Acute coronary syndrome usually results from the buildup of fatty deposits (plaques) in and on the walls of coronary arteries, the blood vessels delivering oxygen and nutrients to heart muscles.
When a plaque deposit ruptures or splits, a blood clot forms. This clot obstructs the flow of blood to heart muscles.
When the supply of oxygen to cells is too low, cells of the heart muscles can die. The death of cells â resulting in damage to muscle tissues â is a heart attack (myocardial infarction).
Even when there is no cell death, an inadequate supply of oxygen still results in heart muscles that don't work correctly or efficiently. This dysfunction may be temporary or permanent. When acute coronary syndrome doesn't result in cell death, it is called unstable angina.