I21.9 ICD-10-CA code: Acute myocardial infarction, unspecified
I21.9 is the ICD-10-CA code for “Acute myocardial infarction, unspecified” in CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026.
Official description
I21.9Acute myocardial infarction, unspecified
Short description: Acute myocardial infarction unspecified
ICD-10-CA · Canada · Also written I219
Index terms
Entries in CIHI’s alphabetical index that lead to I21.9. Searching the index by the condition the note names is how coders reach this code.
- Cardiorrhexis
- Accident, cardiac
- Accident, coronary
- Clot (blood), coronary
- Embolism (septic), cardiac
- Infarct, infarction (of), heart
- Embolism (septic), heart (fatty)
- Rupture, ruptured, artery, heart
- Embolism (septic), vein, coronary
- Infarct, infarction (of), cardiac
- Rupture, ruptured, cardiac (wall)
- Embolism (septic), artery, coronary
- Rupture, ruptured, artery, coronary
- Occlusion, occluded, coronary (artery)
- Rupture, ruptured, blood vessel, heart
- Infarct, infarction (of), coronary artery
- Rupture, ruptured, myocardium, myocardial
- Thromboembolism, coronary (artery) (vein)
- Infarct, infarction (of), ventricle (heart)
- Rupture, ruptured, coronary (artery) (thrombotic)
- Embolism (septic), coronary (artery or vein) (systemic)
- Infarct, infarction (of), heart, with diabetes mellitus
- Dissection, artery NEC, coronary (nonruptured), ruptured
- Apoplexia, apoplexy, apoplectic, heart (auricle) (ventricle)
- Thrombosis, thrombotic (multiple) (progressive) (septic) (vein) (vessel), mural
- Thrombosis, thrombotic (multiple) (progressive) (septic) (vein) (vessel), cardiac
- Thrombosis, thrombotic (multiple) (progressive) (septic) (vein) (vessel), parietal
- Thrombosis, thrombotic (multiple) (progressive) (septic) (vein) (vessel), intramural
- Thrombosis, thrombotic (multiple) (progressive) (septic) (vein) (vessel), endocardial
- Thrombosis, thrombotic (multiple) (progressive) (septic) (vein) (vessel), coronary (artery) (vein)
- Infarct, infarction (of), myocardium, myocardial (acute or with a stated duration of 4 weeks or less)
- Thrombosis, thrombotic (multiple) (progressive) (septic) (vein) (vessel), artery, arteries (postinfectional), coronary
- Infarct, infarction (of), myocardium, myocardial (acute or with a stated duration of 4 weeks or less), with diabetes mellitus
- Aneurysm (anastomotic) (artery) (cirsoid) (diffuse) (false) (fusiform) (multiple) (saccular), coronary (arteriosclerotic) (artery), ruptured
- Aneurysm (anastomotic) (artery) (cirsoid) (diffuse) (false) (fusiform) (multiple) (saccular), heart (wall) (chronic or with a stated duration of over 4 weeks), acute or with a stated duration of 4 weeks or less
Notes for I21.9
As CIHI prints them, with any note I21.9 takes from the headings above it.
Includes
- Myocardial infarction (acute) NOS
- Myocardial infarction specified as acute or with a stated duration of 4 weeks (28 days) or less from onsetFrom I21 Acute myocardial infarction
- With mention of hypertension (I10-I15)From I20-I25 Ischaemic heart diseases
Use additional code
Add a code for this detail when the note documents it.
- Use additional code from category (E10-E14) with fourth and fifth characters .52 to classify any associated diabetes mellitus.From I21 Acute myocardial infarction
- Use additional code from subcategory (R94.3-) to identify abnormal results of cardiovascular function studiesFrom I21 Acute myocardial infarction
- Use additional code to identify presence of hypertension.From I20-I25 Ischaemic heart diseases
Excludes
Conditions classified elsewhere.
- Certain current complications following acute myocardial infarction (I23.-)myocardial infarction:• old (I25.2)• specified as chronic or with a stated duration of more than 4 weeks (more than 28 days) from onset (I25.8)• subsequent (I22.-)postmyocardial infarction syndrome (I24.1)From I21 Acute myocardial infarction
- Certain:• conditions originating in the perinatal period (P00-P96)• infectious and parasitic diseases (A00-B99)complications of pregnancy, childbirth and the puerperium (O00-O99)congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)endocrine, nutritional and metabolic diseases (E00-E90)injury, poisoning and certain other consequences of external causes (S00-T98)neoplasms (C00-D48)symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99)systemic connective tissue disorders (M30-M36)transient cerebral ischaemic attacks and related syndromes (G45.-)From Chapter 9: Diseases of the circulatory system (I00-I99)
Note
- For morbidity, duration as used in categories (I21, I22, I24 and I25) refers to the interval elapsing between onset of the ischaemic episode and admission to care.From I20-I25 Ischaemic heart diseases
Where I21.9 sits
- 1ChapterChapter 9: Diseases of the circulatory system (I00-I99)
- 2Block I20-I25Ischaemic heart diseases
- 3Category I21Acute myocardial infarction
- 4Valid code I21.9Acute myocardial infarction, unspecified
Source and release
- Data release
- ICD-10-CA · FY 2026–2027
- Effective date
- Apr 1, 2026
- Publisher
- CIHI
This page is built from the ICD-10-CA catalog that Vero Codes reads when it suggests codes: Canadian Institute for Health Information’s FY 2026–2027 release, imported from the publisher’s file and checked against it. The description, notes and structured data come from the same record.
Frequently asked questions
What does ICD-10-CA code I21.9 mean?
I21.9 is the ICD-10-CA code for “Acute myocardial infarction, unspecified” in CIHI’s ICD-10-CA FY 2026–2027 release.
Where is I21.9 in ICD-10-CA?
I21.9 sits under I21 Acute myocardial infarction, within I20-I25 Ischaemic heart diseases, within Chapter 9: Diseases of the circulatory system (I00-I99).
What coding notes apply to I21.9?
ICD-10-CA lists Includes, Use additional code, Excludes, Note notes for I21.9, including those from the headings it sits under. They are listed on this page with where each one comes from.
Which ICD-10-CA release does this page use?
It uses CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026 to Mar 31, 2027. It is a reference: confirm the code against the current list and the payer’s rules before you submit it.