ICD-10-CM › I00-I99 › I20-I25 › I21 Acute myocardial infarction › I21.9
I21.9
Acute myocardial infarction, unspecified
ValidICD-10-CM diagnosis code.
Valid for claims with a date of service in the current code year.
What has happened to this code
Every change the publisher made, from 2018 to now.
- FY2018 Added to the code set Acute myocardial infarction, unspecified
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)
How CDC's index refers to this code
Wording from the official alphabetic index. Much of it appears nowhere in the code description, which is why a search for the everyday phrase so often finds nothing.
- Clot > heart
- Cardiorrhexis
- Embolism > heart
- Accident > cardiac
- Embolism > cardiac
- Vasospasm > retina
- Accident > coronary
- Embolism > coronary
- Hollenhorst's plaque
- Body, bodies > cytoid
- Embolism > ophthalmic
- Plaque > Hollenhorst's
- Attack, attacks > heart
- Microembolism > retinal
- Attack, attacks > coronary
- Embolism > retina, retinal
- Necrosis, necrotic > heart
- Embolism > artery > retinal
- Infarct, infarction > heart
- Embolism > artery > coronary
- Rupture, ruptured > coronary
- Infarct, infarction > cardiac
- Aneurysm > coronary > ruptured
- Embolism > artery > ophthalmic
- Occlusion, occluded > coronary
- Thrombosis, thrombotic > heart
- Thrombosis, thrombotic > mural
- Infarct, infarction > ventricle
- Occlusion, occluded > thrombotic
- Thrombosis, thrombotic > cardiac
- Thrombosis, thrombotic > coronary
- Thrombosis, thrombotic > parietal
- Rupture, ruptured > artery > heart
- Thrombosis, thrombotic > ventricle
- Thrombosis, thrombotic > intramural
- Ischemia, ischemic > retina, retinal
- Spasm, spastic, spasticity > retinal
- Thrombosis, thrombotic > endocardial
- Infarct, infarction > coronary artery
- Infarct, infarction > retina, retinal
Showing 40 of 65 index phrases.
Codes in the same group
| Code | Description | Status |
|---|---|---|
| I21.0 | ST elevation (STEMI) myocardial infarction of anterior wall | Not billable |
| I21.1 | ST elevation (STEMI) myocardial infarction of inferior 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.A | Other type of myocardial infarction | Not billable |
| I21.B | Myocardial infarction with coronary microvascular dysfunction | Valid |