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I22

Non-Billable (Header)

Subsequent ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction

Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)

What This Code Means

I22 is the ICD-10-CM diagnosis code for subsequent st elevation (stemi) and non-st elevation (nstemi) myocardial infarction. I22 sits in the ICD-10-CM chapter for diseases of the circulatory system (i00-i99), within the section covering ischemic heart diseases (i20-i25).

Header codes like I22 cannot be reported on claims directly — they organize child codes that share clinical context but the actual diagnosis must be coded to the highest level of specificity supported by the documentation. Coders should look at I22's child codes and select the one that matches the patient's documented presentation, since payers reject header codes submitted as the primary diagnosis. For risk adjustment workflows, header codes never contribute to a Medicare Advantage member's RAF score on their own; only billable child codes that happen to map to a payment HCC affect risk-adjusted plan payments.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for I22 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Includes

  • acute myocardial infarction occurring within four weeks (28 days) of a previous acute myocardial infarction, regardless of site
  • cardiac infarction
  • coronary (artery) embolism
  • coronary (artery) occlusion
  • coronary (artery) rupture
  • coronary (artery) thrombosis
  • infarction of heart, myocardium, or ventricle
  • recurrent myocardial infarction
  • reinfarction of myocardium
  • rupture of heart, myocardium, or ventricle
  • subsequent type 1 myocardial infarction

Excludes 1 — Do NOT code together

  • subsequent myocardial infarction, type 2 (I21.A1)
  • subsequent myocardial infarction of other type (type 3) (type 4) (type 5) (I21.A9)

Use Additional Code

  • 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)

Child Codes

Code Hierarchy

I22Subsequent ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction
I22Subsequent ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction

More on I22

Referenced in blog posts

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