Curriculum · Cardiovascular and Hypertension
ST-elevation myocardial infarction
What it is
Ischemic heart disease divides into the clinically silent, that is asymptomatic, and the symptomatic. The symptomatic side holds stable angina, with symptoms on exertion, and the acute coronary syndromes: unstable angina, non ST-segment elevation MI and ST-segment elevation MI. Behind all of them is the atherosclerotic plaque in the intima and media: progression of the atherosclerotic plaque, then a ruptured plaque, then thrombosis formation.
The etiology is written the same way elsewhere: rupture of unstable atherosclerotic plaques with subsequent thrombosis or partial obstruction of the coronary arteries. There are around 1.0 million cases of myocardial infarction per year in the US.
What raises the risk
Elevated cholesterol levels, and LDL cholesterol is the single most important subgroup that carries risk for IHD. Then smoking, hypertension, physical inactivity and exercise, obesity and diabetes mellitus. The major uncontrollable risk factors are age, sex and genetics.
Set out the other way, the invariable risk factors are geographic origin, age, sex, family history and genetic disposition, the last including elevated lipoprotein(a) and familial hypercholesterolemia. The variable ones are psychosocial factors such as stress; lifestyle factors, that is smoking, unhealthy diet and lack of exercise; pre-existing conditions, that is diabetes mellitus, hypertension and chronic inflammation; and dyslipidemia, with LDL up and HDL down.