AMI: Acute myocardial infarction. A heart attack.

The term "myocardial infarction" focuses on the heart muscle (the myocardium) and the changes that occur in it due to sudden (acute) deprivation of circulating blood. The main change is death (necrosis) of myocardial tissue.

The interruption of blood is usually caused by arteriosclerosis with narrowing of the coronary arteries, the culminating event being a thrombosis (clot). The word "infarction" comes from the Latin "infarcire" meaning "to plug up or cram." It refers to the clogging of the artery.