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ICD-10-CM 2027 diagnosis code

I21.0ST elevation (STEMI) myocardial infarction of anterior wall

Not billable — use a more specific code

I21.0 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About I21.0

I21.0 is the ICD-10-CM diagnosis code for ST elevation (STEMI) myocardial infarction of anterior wall. It belongs to category I21 (acute myocardial infarction), block I20-I25 (ischemic heart diseases) and chapter 9 (diseases of the circulatory system). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

Within I21 (acute myocardial infarction), I21.0 is specifically for ST elevation (STEMI) myocardial infarction of anterior wall. Related codes cover ST elevation (STEMI) myocardial infarction of inferior wall (I21.1), ST elevation (STEMI) myocardial infarction of other sites (I21.2), ST elevation (STEMI) myocardial infarction of unspecified site (I21.3), Non-ST elevation (NSTEMI) myocardial infarction (I21.4), unspecified (I21.9), other type of myocardial infarction (I21.A) and myocardial infarction with coronary microvascular dysfunction (I21.B).

To report this condition, pick the subcode that matches the documentation: I21.01 (artery), I21.02 (artery) and I21.09 (wall).

Use an additional code, if applicable, to identify: exposure to environmental tobacco smoke (Z77.22), history of tobacco dependence (Z87.891), occupational exposure to environmental tobacco smoke (Z57.31), status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility (Z92.82), tobacco dependence (F17.-) and 1 more.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under I21.0

Coding notes

Applicable toConditions and synonyms classified to this code
  • Type 1 ST elevation myocardial infarction of anterior wall

Notes that apply from higher levels

Instructions written at a parent level also apply to I21.0.

› From I21 Acute myocardial infarction
Includes
  • cardiac infarction
  • coronary (artery) embolism
  • coronary (artery) occlusion
  • coronary (artery) rupture
  • coronary (artery) thrombosis
  • infarction of heart, myocardium, or ventricle
  • myocardial infarction specified as acute or with a stated duration of 4 weeks (28 days) or less from onset
Excludes2
  • old myocardial infarction (I25.2)
  • postmyocardial infarction syndrome (I24.1)
  • subsequent type 1 myocardial infarction (I22.-)
Use additional code
  • code, if applicable, to identify:
  • exposure to environmental tobacco smoke (Z77.22)
  • history of tobacco dependence (Z87.891)
  • occupational exposure to environmental tobacco smoke (Z57.31)
  • status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility (Z92.82)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)

Broader instructions also apply from I20-I25 Ischemic heart diseases and Chapter 9: Diseases of the circulatory system.

Codes whose notes reference I21.0

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about I21.0

Is I21.0 billable?

No. I21.0 is a header code. Report one of its more specific subcodes instead.