I21.29
ST elevation (STEMI) myocardial infarction involving other sites
HCC risk adjustment mapping
CMS-HCC V28
Acute Myocardial Infarction
CMS-HCC ESRD V24
Acute Myocardial Infarction
RxHCC V08
Coronary Artery Disease
Coding notes
Excludes 1 never coded together · Excludes 2 may co-exist
Acute transmural myocardial infarction of other sites Apical-lateral transmural (Q wave) infarction (acute) Basal-lateral transmural (Q wave) infarction (acute) High lateral transmural (Q wave) infarction (acute) Lateral (wall) NOS transmural (Q wave) infarction (acute) Posterior (true) transmural (Q wave) infarction (acute) Posterobasal transmural (Q wave) infarction (acute) Posterolateral transmural (Q wave) infarction (acute) Posteroseptal transmural (Q wave) infarction (acute) Septal transmural (Q wave) infarction (acute) NOS
Type 1 ST elevation myocardial infarction of other sites
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
old myocardial infarction (I25.2) postmyocardial infarction syndrome (I24.1) subsequent type 1 myocardial infarction (I22.-)
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)
the presence of hypertension (I10-I1A)
certain conditions originating in the perinatal period (P04-P96) certain infectious and parasitic diseases (A00-B99) complications of pregnancy, childbirth and the puerperium (O00-O9A) congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99) endocrine, nutritional and metabolic diseases (E00-E88) injury, poisoning and certain other consequences of external causes (S00-T88) neoplasms (C00-D49) symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94) systemic connective tissue disorders (M30-M36) transient cerebral ischemic attacks and related syndromes (G45.-)
Official Guidelines for I21.29
FY 2026 ›Sections that reference I21.29
- I.C.9.e.1)Type 1 ST elevation myocardial infarction (STEMI) and non-
… Subcategories I21.0-I21.2 and code I21.3 are used for type 1 ST elevation myocardial infarction (STEMI). …
- I.C.9.e.2)Acute myocardial infarction, unspecified
Code I21.9, Acute myocardial infarction, unspecified, is the default for unspecified acute myocardial infarction or unspecified type. …
- I.C.9.e.4)Subsequent acute myocardial infarction
… the 4 week time frame of the initial AMI. A code from category I22 must be used in conjunction with a code from category I21. The sequencing of the I22 and I21 codes depends on the circumstances of the encounter. …
- I.C.9.e.5)Other Types of Myocardial Infarction
… 2 myocardial infarction (myocardial infarction due to demand ischemia or secondary to ischemic imbalance) is assigned to code I21.A1, Myocardial infarction type 2 with the underlying cause coded first, if applicable. …
- I.C.9.e.6)Myocardial Infarction with Coronary Microvascular Dysfunction
… Code I21.B, Myocardial infarction with coronary microvascular dysfunction, is assigned for myocardial infarction with coronary …
Sections whose FY 2026 text names I21.29, its I21 category, or a range containing it — the chapter guidance above is the authoritative source.
Find I21.29 in the alphabetic index
8 index paths lead to this code
- Infarct, infarction › myocardium, myocardial › ST elevation › lateral
- Infarct, infarction › myocardium, myocardial › ST elevation › posterior
- Infarct, infarction › myocardium, myocardial › ST elevation › septal
- Infarct, infarction › myocardium, myocardial › ST elevation › specified NEC
- Infarct, infarction › myocardium, myocardial › transmural › lateral NEC
- Infarct, infarction › myocardium, myocardial › transmural › posterior NEC
- Infarct, infarction › myocardium, myocardial › transmural › septal NEC
- Infarct, infarction › myocardium, myocardial › transmural › specified NEC