I21: Acute myocardial infarction

Codes under I21 (Acute myocardial infarction). A ✓ marks a billable (fully specified) code; category codes without a ✓ are not billable on their own.

Code	Description	Billable
I21.0	ST elevation (STEMI) myocardial infarction of anterior wall	—
I21.01	ST elevation (STEMI) myocardial infarction involving left main coronary artery	✓
I21.1	ST elevation (STEMI) myocardial infarction of inferior wall	—
I21.02	ST elevation (STEMI) myocardial infarction involving left anterior descending coronary artery	✓
I21.2	ST elevation (STEMI) myocardial infarction of other sites	—
I21.3	ST elevation (STEMI) myocardial infarction of unspecified site	✓
I21.4	Non-ST elevation (NSTEMI) myocardial infarction	✓
I21.09	ST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wall	✓
I21.9	Acute myocardial infarction, unspecified	✓
I21.11	ST elevation (STEMI) myocardial infarction involving right coronary artery	✓
I21.19	ST elevation (STEMI) myocardial infarction involving other coronary artery of inferior wall	✓
I21.21	ST elevation (STEMI) myocardial infarction involving left circumflex coronary artery	✓
I21.29	ST elevation (STEMI) myocardial infarction involving other sites	✓
I21.A	Other type of myocardial infarction	—
I21.A1	Myocardial infarction type 2	✓
I21.A9	Other myocardial infarction type	✓
I21.B	Myocardial infarction with coronary microvascular dysfunction	✓

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Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.

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