I21
Acute myocardial infarction
Not billable — category only FY2026 2025-10-01 → 2026-09-30
Exclusions 13 never code together
I21code
I00-I99chapter
Excludes2
- certain conditions originating in the perinatal period (P04-P96)P04-P96
- certain infectious and parasitic diseases (A00-B99)A00-B99
- complications of pregnancy, childbirth and the puerperium (O00-O9A)O00-O9A
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Q00-Q99
- endocrine, nutritional and metabolic diseases (E00-E88)E00-E88
- injury, poisoning and certain other consequences of external causes (S00-T88)S00-T88
- neoplasms (C00-D49)C00-D49
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)R00-R94
- systemic connective tissue disorders (M30-M36)M30-M36
- transient cerebral ischemic attacks and related syndromes (G45.-)G45.-
Excludes2 — not included here, but the patient may have both. Code both when documented.
Instructional notes 15
I21code
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
Use additional code
- code, if applicable, to identify:
- exposure to environmental tobacco smoke (Z77.22)Z77.22Z77.22Z77.22
- history of tobacco dependence (Z87.891)Z87.891Z87.891Z87.891
- occupational exposure to environmental tobacco smoke (Z57.31)Z57.31Z57.31Z57.31
- status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility (Z92.82)Z92.82Z92.82Z92.82
- tobacco dependence (F17.-)F17.-F17.-F17.-
- tobacco use (Z72.0)Z72.0Z72.0Z72.0
Index entries leading here filed at null
No alphabetic index entry points at this code.
Subordinate codes 8
I21.0 ST elevation (STEMI) myocardial infarction of anterior wall I21.1 ST elevation (STEMI) myocardial infarction of inferior wall I21.2 ST elevation (STEMI) myocardial infarction of other sites I21.3 ST elevation (STEMI) myocardial infarction of unsp site I21.4 Non-ST elevation (NSTEMI) myocardial infarction I21.9 Acute myocardial infarction, unspecified I21.A Other type of myocardial infarction I21.B Myocardial infarction with coronary microvascular dysfnct
Medications 1
MED-RT files conditions by MeSH, which carves the world differently from ICD-10. These are name matches on this code's description, offered as candidates — not as an assertion that they are this code.
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.