Myocardial infarction is the death of an area of heart muscle due to an abrupt cutoff of its blood supply. It is usually the result of the rupture of an atherosclerotic plaque and the formation of a clot in a coronary artery.
This is an emergency: the longer the muscle is without oxygen, the more of it dies. A key role in its development is played by “bad” cholesterol, and the diagnosis is confirmed by a troponin test.
What happens during a heart attack
Over years a cholesterol plaque builds up in the walls of the coronary arteries (atherosclerosis). When it ruptures, a clot forms on its surface that completely blocks the vessel. The muscle below the blockage stops receiving oxygen and begins to die — that is a heart attack.
Less often the cause is a marked spasm of a coronary artery. The extent of damage depends on which vessel closed and how quickly blood flow was restored.
How to recognize it: warning signs
The classic symptom is a pressing or squeezing pain/discomfort behind the breastbone or on the left, lasting longer than a few minutes (or coming and going). The pain may radiate to the arm, back, neck or jaw. Shortness of breath, cold sweat, nausea, weakness and dizziness often join in.
In women, older people and those with diabetes, a heart attack more often runs atypically: without marked pain, with unusual fatigue, shortness of breath or abdominal discomfort.
Why you must not wait
“Time is muscle”: with every minute more myocardium dies, and irreversible changes build up within the first hours. Early restoration of blood flow (stenting or thrombolysis) saves muscle and life.
If a heart attack is suspected you must call an ambulance immediately — even if you are unsure. Do not drive yourself and do not “wait out” the pain.
Causes, risk factors and diagnosis
The main risk factors are smoking, high blood pressure, high LDL cholesterol, diabetes, obesity, physical inactivity and heredity. The diagnosis is made from symptoms, the ECG and a blood troponin test — a protein that enters the blood when heart cells die.
Calculate using this marker
Calculators where Myocardial infarction is used directly:
Frequently asked questions
How is a heart attack different from angina?
Angina is a temporary shortfall of blood flow on exertion; the pain passes at rest within minutes and the muscle does not die. A heart attack is a persistent blockage: the pain is prolonged, is not relieved by rest, and part of the myocardium dies. This is a reason for an emergency call.
Can you have a heart attack “on your feet”?
Yes, there are “silent” heart attacks with almost no symptoms, especially in diabetes and in older people. They are sometimes found later on an ECG. So any unexplained episodes of shortness of breath, weakness or chest discomfort should be discussed with a doctor.