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I21Non-billableSave

I21 - Acute myocardial infarction

ICD-10-CM Chapter 9: Diseases of the circulatory system · I20-I25 Ischemic heart diseases (I20-I25) · Top-level category · FY2027

Coding Guidance

I21 is a non-billable heading. Report one of the 8 more specific codes below.

Includes, Excludes and Coding Notes

IncludesFrom I21

Conditions this code covers.

  • 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
Excludes 2 — Not Included HereFrom I21

Not part of this code; report both codes when the patient has both conditions.

  • old myocardial infarction (I25.2)
  • postmyocardial infarction syndrome (I24.1)
  • subsequent type 1 myocardial infarction (I22.-)
Use Additional CodeFrom I21

Add a secondary code to identify the associated condition or cause when it is documented.

  • 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)
Code AlsoFrom I20-I25 Ischemic heart diseases (I20-I25)

Report an additional code when both conditions apply.

  • the presence of hypertension (I10-I1A)
Excludes 2 — Not Included HereFrom Chapter I00-I99

Not part of this code; report both codes when the patient has both conditions.

  • 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.-)

More Specific Codes (8)

I21.0ST elevation (STEMI) myocardial infarction of anterior wall→I21.1ST elevation (STEMI) myocardial infarction of inferior wall→I21.2ST elevation (STEMI) myocardial infarction of other sites→I21.3ST elevation (STEMI) myocardial infarction of unspecified site→I21.4Non-ST elevation (NSTEMI) myocardial infarction→I21.9Acute myocardial infarction, unspecified→I21.AOther type of myocardial infarction→I21.BMyocardial infarction with coronary microvascular dysfunction→

Related condition guides

Documentation requirements, coding pitfalls and FAQs for conditions coded with I21.