ICD-10-CM › I00-I99 › I20-I25 › I21 Acute myocardial infarction › I21.1

I21.1

ST elevation (STEMI) myocardial infarction of inferior wall

Not billableICD-10-CM diagnosis code.

This code exists but cannot be submitted on its own. It groups the more specific codes beneath it.

A category header for its whole life, FY2016 onwards. It has never been valid for submission on its own.

Submit one of these 2 more specific codes instead:

  • I21.11 ST elevation (STEMI) myocardial infarction involving right coronary artery
  • I21.19 ST elevation (STEMI) myocardial infarction involving other coronary artery of inferior wall

What has happened to this code

Every change the publisher made, from 2012 to now. Entries marked draft are from the pre-implementation releases: ICD-10 took effect on 1 October 2015, so nothing before FY2016 was ever valid on a claim.

  1. FY2012 Added to the draft code set draft ST elevation (STEMI) myocardial infarction of inferior wall

Official coding rules

Published by CDC for FY2027. A rule attached to a category binds every code beneath it, so the rules inherited from this code's ancestors are shown with the code they come from.

Inherited from I21 Acute myocardial infarction

Excludes2 - not included here

  • 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)

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

Inherited from the I20-I25 section Ischemic heart diseases (I20-I25)

Code also

  • the presence of hypertension (I10-I1A)

Codes in the same group

CodeDescriptionStatus
I21.0 ST elevation (STEMI) myocardial infarction of anterior wall Not billable
I21.2 ST elevation (STEMI) myocardial infarction of other sites Not billable
I21.3 ST elevation (STEMI) myocardial infarction of unspecified site Valid
I21.4 Non-ST elevation (NSTEMI) myocardial infarction Valid
I21.9 Acute myocardial infarction, unspecified Valid
I21.A Other type of myocardial infarction Not billable
I21.B Myocardial infarction with coronary microvascular dysfunction Valid