I21.29 — ST elevation (STEMI) myocardial infarction involving other sites
Is I21.29 billable?
Yes — I21.29 is billable for FY2027. I21.29 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. I21.29 may be submitted for encounters from October 1, 2026 through September 30, 2027.
I21.29 at a glance
| Code | I21.29 |
|---|---|
| Description | ST elevation (STEMI) myocardial infarction involving other sites |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does I21.29 group to?
I21.29 sits in MDC 05 and helps define the logic of 6 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 280Acute Myocardial Infarction, Discharged Alive with MCCmedical
- 281Acute Myocardial Infarction, Discharged Alive with CCmedical
- 282Acute Myocardial Infarction, Discharged Alive without CC/MCCmedical
- 283Acute Myocardial Infarction, Expired with MCCmedical
- 284Acute Myocardial Infarction, Expired with CCmedical
- 285Acute Myocardial Infarction, Expired without CC/MCCmedical
As a secondary diagnosis, I21.29 is a major complication or comorbidity (MCC), which can move a stay into a higher-paying DRG.
How is I21.29 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to I21.29. They show the wording a clinician may have documented, which often differs from the Tabular description.
- 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 › lateralNEC
- Infarct, infarction › myocardium, myocardial › transmural › posteriorNEC
- Infarct, infarction › myocardium, myocardial › transmural › septal NEC
- Infarct, infarction › myocardium, myocardial › transmural › specified NEC
Inclusion terms
Alternative wording in documentation that is classified to I21.29.
- 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
Use additional code — inherited from I21
Report an additional code alongside I21.29 to fully describe the condition. I21.29 is sequenced first.
- 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)
Excludes2 — not included here — inherited from Chapter 9
The conditions below are not part of I21.29, but a patient may have both at the same time. When documentation supports it, I21.29 and the excluded code may both be reported.
- 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.-)
Excludes2 — not included here — inherited from I21
The conditions below are not part of I21.29, but a patient may have both at the same time. When documentation supports it, I21.29 and the excluded code may both be reported.
Code also — inherited from I20-I25
Two codes may be needed to describe the condition fully. Whether I21.29 is sequenced first depends on the reason for the encounter.
- the presence of hypertension (I10-I1A)
How long has I21.29 existed?
I21.29 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.