Illustration of the causes of a myocardial infarction. necrosis of part of the secondary heart muscle through an oxygenation flaw (ischemia). The infarction occurs when one of more coronary arteries become blocked. the heart muscle cells that are irrigated by these arteries are no longer oxygenated. which can lead to their death. The infarct area will no longer contract properly. The obliteration of the coronary artery is linked to an atheromatous plaque. a deposit which can cause a reduction of the arterial lumen (stenosis). It can be caused by a clot. a piece of the existing atheromatous plaque that detaches itself. It can be caused by a coronary spasm. a dramatic reduction of the arterial lumen linked to the vasomotricity of the arteries.