ICD-10-CM
ICD-10 code for Heart attack: I21.9
The CDC title for "Heart attack" is I21 (Acute myocardial infarction), a header that is not billable. When nothing more specific is documented, the billable code is I21.9, Acute myocardial infarction, unspecified.
Source: CDC ICD-10-CM FY2027 order file dated June 16, 2026. Publisher page
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Codes under I21, then other CDC titles that name acute myocardial infarction
A header groups codes and is not billed. A billable code is one you can report.
- I21Acute myocardial infarctionHeader
- I21.0ST elevation (STEMI) myocardial infarction of anterior wallHeader
- I21.01ST elevation (STEMI) myocardial infarction involving left main coronary arteryBillable
- I21.02ST elevation (STEMI) myocardial infarction involving left anterior descending coronary arteryBillable
- I21.09ST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wallBillable
- I21.1ST elevation (STEMI) myocardial infarction of inferior wallHeader
- I21.11ST elevation (STEMI) myocardial infarction involving right coronary arteryBillable
- I21.19ST elevation (STEMI) myocardial infarction involving other coronary artery of inferior wallBillable
- I21.2ST elevation (STEMI) myocardial infarction of other sitesHeader
- I21.21ST elevation (STEMI) myocardial infarction involving left circumflex coronary arteryBillable
- I21.29ST elevation (STEMI) myocardial infarction involving other sitesBillable
- I21.3ST elevation (STEMI) myocardial infarction of unspecified siteBillable
- I21.4Non-ST elevation (NSTEMI) myocardial infarctionBillable
- I21.9Acute myocardial infarction, unspecifiedBillable
- I21.AOther type of myocardial infarctionHeader
- I21.A1Myocardial infarction type 2Billable
- I21.A9Other myocardial infarction typeBillable
- I21.BMyocardial infarction with coronary microvascular dysfunctionBillable
- I23.0Hemopericardium as current complication following acute myocardial infarctionBillable
- I23.1Atrial septal defect as current complication following acute myocardial infarctionBillable
- I23.2Ventricular septal defect as current complication following acute myocardial infarctionBillable
- I23.3Rupture of cardiac wall without hemopericardium as current complication following acute myocardial infarctionBillable
- I23.4Rupture of chordae tendineae as current complication following acute myocardial infarctionBillable
- I23.5Rupture of papillary muscle as current complication following acute myocardial infarctionBillable
- I23.6Thrombosis of atrium, auricular appendage, and ventricle as current complications following acute myocardial infarctionBillable
- I23.8Other current complications following acute myocardial infarctionBillable
Use additional code
The CDC tabular list says to add the code named here after this one when it applies.
From I21. A note on a category applies to every code under it.
Use additional code, if applicable, to identify:
- Z77.22Exposure to environmental tobacco smoke
- Z87.891History of tobacco dependence
- Z57.31Occupational exposure to environmental tobacco smoke
- Z92.82Status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility
- F17.-Tobacco dependence
- Z72.0Tobacco use
Excludes2
Excludes2 means the other condition can be reported with this one when both are documented.
From I21. A note on a category applies to every code under it.
Related conditions
Related pages
- I21.9 code detailsNotes, nearby codes, CMS-HCC group
- Category I21Every code under it
- Chapter 9Diseases of the circulatory system
- ICD-10 codes by conditionA to Z
- Check a list of ICD-10 codes
- Denial code CO-11Diagnosis does not support the procedure
- Denial code CO-146Diagnosis invalid for the date of service
- HCPCS Level II code lookup
Questions
What is the ICD-10 code for Heart attack?
The CDC title for "Heart attack" is I21 (Acute myocardial infarction), a header that is not billable. When nothing more specific is documented, the billable code is I21.9, Acute myocardial infarction, unspecified.
Is I21.9 billable?
Yes. I21.9 is a billable code in the FY2027 ICD-10-CM file. Use a more specific code when the record documents one.
What documentation notes apply to I21.9?
The CDC tabular list gives 3 Excludes2 notes (may be coded together when both are documented), 7 "use additional code" notes for I21.9 and the categories above it. They are listed on this page.
What chapter is I21.9 in?
Chapter 9. Diseases of the circulatory system.
When do ICD-10-CM codes change?
Every October 1, with the new fiscal year file. Some years add April 1 updates. This page uses the FY2027 file, effective October 1, 2026.