Going into detail on what this term means and how it relates to health guidelines. This article may be incomplete.
The term used to describe the most serious of heart attacks, where there is complete occlusion of the vessel from a plaque rupture and subsequent clot (thrombus) formation, causing absolute cessation of blood flow beyond that point. This threatens all of the muscle tissue downstream of this point. The terms STEMI describes the EKG findings (ST segment elevation) which represent "full thickness" injury pattern that will eventually turn into full thickness muscle death or, "infarction" unless opened up right away.