2025 ICD-10-CM Diagnosis Code I21.A9

Other myocardial infarction type

  • I21.A9 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
  • The 2025 edition of ICD-10-CM I21.A9 became effective on October 1, 2024.
  • This is the American ICD-10-CM version of I21.A9 – other international versions of ICD-10 I21.A9 may differ.

Applicable To

  • Myocardial infarction associated with revascularization procedure
  • Myocardial infarction type 3
  • Myocardial infarction type 4a
  • Myocardial infarction type 4b
  • Myocardial infarction type 4c
  • Myocardial infarction type 5

Code First

  • , if applicable, postprocedural myocardial infarction following cardiac surgery (I97.190), or postprocedural myocardial infarction during cardiac surgery (I97.790)

Code Also

  • complication, if known and applicable, such as:
  • (acute) stent occlusion (T82.897-)
  • (acute) stent stenosis (T82.855-)
  • (acute) stent thrombosis (T82.867-)
  • cardiac arrest due to underlying cardiac condition (I46.2)
  • complication of percutaneous coronary intervention (PCI) (I97.89)
  • occlusion of coronary artery bypass graft (T82.218-)

The following code(s) above I21.A9 contain annotation back-references

 that may be applicable to I21.A9:

  • I00I99  Diseases of the circulatory system
  • I20-I25  Ischemic heart diseases
  • I21  Acute myocardial infarction

ICD-10-CM I21.A9 is grouped within Diagnostic Related Group(s) (MS-DRG v42.0):

  • 280 Acute myocardial infarction, discharged alive with mcc
  • 281 Acute myocardial infarction, discharged alive with cc
  • 282 Acute myocardial infarction, discharged alive without cc/mcc
  • 283 Acute myocardial infarction, expired with mcc
  • 284 Acute myocardial infarction, expired with cc
  • 285 Acute myocardial infarction, expired without cc/mcc

Convert I21.A9 to ICD-9-CMCode History

  • 2018 (effective 10/1/2017): New code
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
  • 2021 (effective 10/1/2020): No change
  • 2022 (effective 10/1/2021): No change
  • 2023 (effective 10/1/2022): No change
  • 2024 (effective 10/1/2023): No change
  • 2025 (effective 10/1/2024): No change

Code annotations containing back-references to I21.A9:

  • Type 1 Excludes: I22

Diagnosis Index entries containing back-references to I21.A9:

  • Infarct, infarction
    • myocardium, myocardial (acute) (with stated duration of 4 weeks or less) I21.9
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