ICD-10 I21
Non-Billable HeaderAcute myocardial infarction
About ICD-10-CM I21
ICD-10-CM code I21 represents Acute myocardial infarction. This is a non-billable header code in the Circulatory System chapter (block I21). The 2026 edition of ICD-10-CM I21 became effective on October 1, 2025. Non-billable codes cannot be used as a primary or secondary diagnosis on a claim, use a more specific child code instead.
Type 2 Excludes
Not included here, the excluded code is not part of I21, but a patient may have both conditions at the same time. Both codes may be coded together when applicable.
- old myocardial infarction (I25.2)
- postmyocardial infarction syndrome (I24.1)
- subsequent type 1 myocardial infarction (I22.-)
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
When coding I21, also report these additional codes when applicable.
- 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)
Medicare LCD Coverage for I21
Local Coverage Determinations (LCDs) from CMS MACs that list I21 as a covered diagnosis.
This doesn't mean the code isn't covered, it means no MAC has issued a Local Coverage Determination naming this specific code. Coverage may still apply under National Coverage Determinations or general medical-necessity rules.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing I21.
1 Cigna
CPT Codes Commonly Billed with I21
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 93000 Electrocardiogram for chest pain evaluation Internal Medicine
- 93015 Stress test for chest pain evaluation Cardiovascular Disease
- 93563 Echocardiogram for chest pain evaluation Cardiovascular Disease
- 93565 Transesophageal echocardiogram for chest pain evaluation Cardiovascular Disease
- 93501 Echocardiogram for chest pain evaluation Cardiovascular Disease
- 93598 Intravascular ultrasound for chest pain evaluation Cardiovascular Disease
- 93618 Implantable cardioverter-defibrillator for ventricular tachycardia Cardiovascular Disease
- 93750 Pacemaker insertion for bradycardia Cardiovascular Disease
- 93799 Unlisted cardiovascular procedure Cardiovascular Disease
- 93567 Transesophageal echocardiogram for chest pain evaluation Cardiovascular Disease
Codes Adjacent To I21
Other codes in section I20-I25 (Ischemic heart diseases).
ICD-10 I21, Billing FAQ
Is ICD-10 code I21 billable? +
No, I21 is a non-billable header code. Use a more specific child code from block I21 when submitting claims.
What codes are Type 2 Excludes for I21? +
Type 2 Excludes (may be coded together when both conditions exist): old myocardial infarction (I25.2); postmyocardial infarction syndrome (I24.1); subsequent type 1 myocardial infarction (I22.-)
What CPT codes are commonly billed with I21? +
Procedures frequently paired with I21 include: 93000, 93015, 93563, 93565, 93501.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on July 17, 2026.
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