I21.9: Acute myocardial infarction, unspecified

You are having a heart attack.

The heart is supplied with oxygen-rich blood via the coronary arteries. The coronary arteries are blood vessels that run around the outside of the heart. The coronary arteries can get narrow due to deposits of fat and calcium. Various things favor these deposits. These include smoking, high blood pressure, and other disorders.

When someone has a heart attack, the coronary arteries have become far too narrow or they have closed up completely. As a result, the heart does not get enough oxygen. As a result, the heart muscle gets damaged or dies off.

When someone has a heart attack, they get sudden pains in the chest or arm. They may sweat or feel nauseous. The heart may no longer be working properly. One can then have breathing difficulties and be seriously ill.

Additional indicator

On medical documents, the ICD code is often appended by letters that indicate the diagnostic certainty or the affected side of the body.

  • G: Confirmed diagnosis
  • V: Tentative diagnosis
  • Z: Condition after
  • A: Excluded diagnosis
  • L: Left
  • R: Right
  • B: Both sides

Further information


This information is not intended for self-diagnosis and does not replace professional medical advice from a doctor. If you find an ICD code on a personal medical document, please also note the additional indicator used for diagnostic confidence.
Your doctor will assist you with any health-related questions and explain the ICD diagnosis code to you in a direct consultation if necessary.


Provided by the non-profit organization “Was hab’ ich?” gemeinnützige GmbH on behalf of the Federal Ministry of Health (BMG).