Blocked coronary artery. Computer artwork of a clot (red) in a coronary artery. The clot has been caused by atherosclerosis, the build up of fatty plaques (yellow) on the artery wall. Part of the plaque has come lose and blocked the already narrowed artery. Interruption of the blood flow to the heart often leads to a myocardial infarction (heart attack) and can be fatal.
