The medical term for heart attack is myocardial infarction, usually shortened to MI. It means a section of heart muscle was injured after its blood flow stayed cut off for too long.
Doctors add words in front to say how sudden or where it happened: acute myocardial infarction, or AMI, means it is happening now or just happened, and anterior or inferior points to the wall of the heart involved. On a discharge summary you may also see STEMI or NSTEMI, which describe what the heart tracing showed. Here is how each piece of the term works, and how it differs from cardiac arrest.
At a glance
Medical term
Myocardial infarctionAbbreviations
MI, AMI, STEMI, NSTEMIWord roots
myo muscle, cardi heart, infarction tissue death from lost blood flowUmbrella term
ACS, acute coronary syndromeDo not confuse with
Cardiac arrest, when the heart stops pumpingSpecialty
Cardiology, emergency medicine
Breaking the medical term for heart attack into parts
Myocardial infarction is built from three word parts that students meet again and again.
| Part | Meaning | Seen also in |
|---|---|---|
| myo | Muscle | Myositis, myalgia |
| cardi, cardial | Heart, relating to the heart | Cardiology, pericardial |
| infarction | Death of tissue because blood flow stopped | Cerebral infarction, a type of stroke |
Put together, myocardial infarction means death of heart muscle tissue from a loss of blood flow. Infarction comes from a Latin verb meaning to stuff or plug, a fitting picture of a blocked artery. The damaged area itself is called an infarct.
STEMI, NSTEMI and other words around MI
Notes rarely say just myocardial infarction. They add details that guide treatment.
- STEMI: ST elevation myocardial infarction. The EKG shows a specific raised segment, which usually signals a fully blocked artery and calls for opening it quickly.
- NSTEMI: non ST elevation myocardial infarction. Troponin blood levels reveal injury to the muscle, yet the tracing does not have that raised segment.
- Acute coronary syndrome: the umbrella for sudden reduced blood flow to the heart, including STEMI, NSTEMI and unstable angina.
- Old MI or prior MI: a past heart attack, often seen on tests as scar.
In a history list: "PMH: CAD, NSTEMI s/p PCI to LAD." This reads as coronary artery disease with a past non ST elevation heart attack, treated by opening the left anterior descending artery with a catheter procedure.
Heart attack versus cardiac arrest
People often use these words for the same event, but they mean different things. A heart attack is a plumbing problem: an artery feeding the heart is blocked, and muscle starts to die. The person is usually awake and may feel chest pressure, shortness of breath, sweating, nausea or pain spreading to the arm, jaw or back. Symptoms can be milder or atypical, which happens more often in women, in older adults and in those living with diabetes.
Cardiac arrest is an electrical problem: the heart suddenly stops pumping effectively, and the person collapses and stops breathing normally. A heart attack can trigger cardiac arrest, but most heart attacks do not. If heart attack symptoms seem possible, the safe step is to call 911 or local emergency services right away rather than drive themselves.
Tips for reading cardiology notes
Three habits make heart notes easier. First, look for the word acute, which means the event is current, versus history of or prior, which means it happened before. Second, check which wall is named, such as anterior, inferior or lateral, since that hints at which artery was involved. Third, watch for troponin, the blood test that rises when heart muscle is injured.
For more plain words matched to their clinical names, browse the medical terminology guide.
This page explains vocabulary only. What a heart diagnosis means for you, and what treatment fits, is a conversation for your cardiologist or primary care team.
Frequently asked questions
What do doctors call a heart attack?
Myocardial infarction, abbreviated MI. When it is happening now, doctors often say acute myocardial infarction, or AMI.
Is a heart attack the same as cardiac arrest?
No. A heart attack is a blocked artery that damages heart muscle, while cardiac arrest is when the heart suddenly stops pumping. One can bring on the other, yet they remain two distinct events.
What does infarction mean?
Infarction means tissue death caused by a loss of blood supply. The damaged area is called an infarct, and the term is used for the heart, brain and other organs.
What is the difference between STEMI and NSTEMI?
Both are heart attacks. STEMI has a telltale raised segment on the tracing that typically points to a fully closed artery, while NSTEMI shows injury on blood tests without it.
What is a silent heart attack?
It is a heart attack with mild symptoms or none that a person notices. It may only be found later on an EKG or heart imaging as an old MI.