What are the different types of heart attacks?

When someone has a heart attack (referred to by doctors as a myocardial infarction (MI)) it's a medical emergency. A heart attack happens when there is a loss of blood flow to the heart and if not treated, it can lead to serious damage to the heart muscle.

There are 2 main types of heart attack:

• STEMI (ST-segment elevation myocardial infarction)
• NSTEMI (non-ST-segment elevation myocardial infarction).

Both are caused by blockages in the coronary arteries, but the main difference is the extent of blockage, and the damage caused to the heart.

Using a heart monitoring test called an ECG (electrocardiogram), doctors can see a specific change in the electrical signals in your heart called ‘ST elevation’ when you’ve had a STEMI, which helps them diagnose it.

They will also do a blood test to check your levels of troponin which rise when the heart is injured. 

If your ECG shows ST elevation and you have high troponin blood levels, then your coronary artery that supplies blood to the heart is likely totally blocked and you will be diagnosed with a STEMI heart attack.

If you have had an NSTEMI heart attack, where your coronary artery is partially blocked, your troponin blood levels will be high but your ECG will not show the changes to the electrical signals in your heart that are seen if you’ve had a STEMI heart attack.

A STEMI heart attack needs urgent treatment to clear the blocked artery and restore blood flow to the heart. But, even though it's less severe, an NSTEMI can turn into a STEMI if the blockage is not treated quickly, so urgent medical attention is still needed.

The symptoms of both types of heart attack are the same:

• chest pain (which might feel heavy, tight, or crushing),
• feeling sick
• discomfort like indigestion
• feeling suddenly very anxious. 

As heart attack symptoms can vary, it’s vital you call 999 immediately if you suspect you or somebody else is having a heart attack.

If you’ve had a heart attack and you’re not sure which type you’ve had, ask your doctor or nurse to confirm which one it was. 

What to read next...