ICD-10-CM · Chapter 9 · I00-I99
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
Excludes 2 (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)
Subcodes
Each subcode links to a detail page with full clinical annotations.
| Code | Description | Billable |
|---|---|---|
| I21..0 | ST elevation (STEMI) myocardial infarction of anterior wall | No |
| I21..01 | ST elevation (STEMI) myocardial infarction involving left main coronary artery | Yes |
| I21..02 | ST elevation (STEMI) myocardial infarction involving left anterior descending coronary artery | Yes |
| I21..09 | ST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wall | Yes |
| I21..1 | ST elevation (STEMI) myocardial infarction of inferior wall | No |
| I21..11 | ST elevation (STEMI) myocardial infarction involving right coronary artery | Yes |
| I21..19 | ST elevation (STEMI) myocardial infarction involving other coronary artery of inferior wall | Yes |
| I21..2 | ST elevation (STEMI) myocardial infarction of other sites | No |
| I21..21 | ST elevation (STEMI) myocardial infarction involving left circumflex coronary artery | Yes |
| I21..29 | ST elevation (STEMI) myocardial infarction involving other sites | Yes |
| I21..3 | ST elevation (STEMI) myocardial infarction of unspecified site | Yes |
| I21..4 | Non-ST elevation (NSTEMI) myocardial infarction | Yes |
| I21..9 | Acute myocardial infarction, unspecified | Yes |
| I21..A | Other type of myocardial infarction | No |
| I21..A1 | Myocardial infarction type 2 | Yes |
| I21..A9 | Other myocardial infarction type | Yes |
| I21..B | Myocardial infarction with coronary microvascular dysfunction | Yes |
Plain-language term for this code
The following entry in the US Medical Glossary corresponds to ICD-10-CM category I21:
- Heart Attack — Infarto de miocardio
Last reviewed: September 2026