I21.4 NON-ST ELEVATION (NSTEMI) MYOCARDIAL INFARCTION

Code Information

  • Diagnosis Code: I21.4
  • Short Description: Non-ST elevation (NSTEMI) myocardial infarction
  • Long Description: Non-ST elevation (NSTEMI) myocardial infarction
  • Code Version: 2025 ICD-10-CM

The code I21.4 is VALID for claim submission

Code Classification

Synonyms

  • Acute anterior non-ST segment elevation myocardial infarction
  • Acute anterior non-ST segment elevation myocardial infarction with right ventricular involvement
  • Acute anteroseptal myocardial infarction
  • Acute inferior non-ST segment elevation myocardial infarction
  • Acute inferior non-ST segment elevation myocardial infarction of right ventricle
  • Acute myocardial infarction of anterior wall involving right ventricle
  • Acute myocardial infarction of anterolateral wall
  • Acute myocardial infarction of inferior wall
  • Acute myocardial infarction of inferior wall
  • Acute myocardial infarction of inferior wall
  • Acute myocardial infarction of inferolateral wall
  • Acute myocardial infarction of right ventricle
  • Acute myocardial infarction of right ventricle
  • Acute myocardial infarction of right ventricle
  • Acute non-Q wave infarction
  • Acute non-Q wave infarction - anterolateral
  • Acute non-Q wave infarction - anteroseptal
  • Acute non-Q wave infarction - inferior
  • Acute non-Q wave infarction - inferolateral
  • Acute non-Q wave infarction - lateral
  • Acute non-Q wave infarction - widespread
  • Acute non-ST segment elevation myocardial infarction
  • Acute non-ST segment elevation myocardial infarction of right ventricle
  • Acute subendocardial infarction
  • Acute widespread myocardial infarction
  • EKG: myocardial infarction
  • EKG: subendocardial infarct
  • Non-Q wave myocardial infarction
  • Postoperative myocardial infarction
  • Postoperative subendocardial myocardial infarction
  • Subendocardial myocardial infarction
  • Subendocardial myocardial infarction

Diagnostic Related Group(s)

The code I21.4 is grouped in the following Diagnostic Related Group(s) MS-DRG V43.0

  1. Acute Myocardial Infarction, Discharged Alive With Mcc (280)
  2. Acute Myocardial Infarction, Discharged Alive With Cc (281)
  3. Acute Myocardial Infarction, Discharged Alive Without Cc/mcc (282)
  4. Acute Myocardial Infarction, Expired With Mcc (283)
  5. Acute Myocardial Infarction, Expired With Cc (284)
  6. Acute Myocardial Infarction, Expired Without Cc/mcc (285)

References to Index of Diseases and Injuries

The code I21.4 has the following ICD-10-CM references to the Index of Diseases and Injuries

  • Inclusion Terms:
    • Acute subendocardial myocardial infarction
    • Non-Q wave myocardial infarction NOS
    • Nontransmural myocardial infarction NOS
    • Type 1 non-ST elevation myocardial infarction

Crosswalk Information

ICD-10 Code ICD-9 Code ICD-9 Description
I21.4 Right Arrow 410.71 Subendo infarct, initial
This ICD-10 to ICD-9 data is based on the 2018 General Equivalency Mapping (GEM) files published by the Centers for Medicare & Medicaid Services (CMS) for informational purposes only. The data is not an ICD-10 conversion tool and doesn’t guarantee clinical accuracy.

Similar Codes

ICD-10 Code ICD-10 Description
I21 Acute myocardial infarction
I21.0 ST elevation (STEMI) myocardial infarction of anterior wall
I21.01 ST elevation (STEMI) myocardial infarction involving left main coronary artery
I21.02 ST elevation (STEMI) myocardial infarction involving left anterior descending coronary artery
I21.09 ST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wall
I21.1 ST elevation (STEMI) myocardial infarction of inferior wall
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
I21.2 ST elevation (STEMI) myocardial infarction of other sites
I21.21 ST elevation (STEMI) myocardial infarction involving left circumflex coronary artery
I21.29 ST elevation (STEMI) myocardial infarction involving other sites
I21.3 ST elevation (STEMI) myocardial infarction of unspecified site
I21.9 Acute myocardial infarction, unspecified
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
This page was last updated on: 10/1/2025
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