2020 ICD-10-CM Diagnosis Code I21

Acute myocardial infarction

    2016 2017 2018 - Revised Code 2019 2020 Non-Billable/Non-Specific Code
  • I21 should not be used for reimbursement purposes as there are multiple codes below it that contain a greater level of detail.
  • The 2020 edition of ICD-10-CM I21 became effective on October 1, 2019.
  • This is the American ICD-10-CM version of I21 - other international versions of ICD-10 I21 may differ.
Use Additional
Use Additional Help
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation. In most cases the manifestation codes will have in the code title, "in diseases classified elsewhere." Codes with this title are a component of the etiology/manifestation convention. The code title indicates that it is a manifestation code. "In diseases classified elsewhere" codes are never permitted to be used as first listed or principle diagnosis codes. They must be used in conjunction with an underlying condition code and they must be listed following the underlying condition.
  • code, if applicable, to identify:
  • exposure to environmental tobacco smoke (
    ICD-10-CM Diagnosis Code Z77.22

    Contact with and (suspected) exposure to environmental tobacco smoke (acute) (chronic)

      2016 2017 2018 2019 2020 Billable/Specific Code
    Applicable To
    • Exposure to second hand tobacco smoke (acute) (chronic)
    • Passive smoking (acute) (chronic)
    Type 1 Excludes
    Type 2 Excludes
    • occupational exposure to environmental tobacco smoke (Z57.31)
    Z77.22
    )
  • history of tobacco dependence (
    ICD-10-CM Diagnosis Code Z87.891

    Personal history of nicotine dependence

      2016 2017 2018 2019 2020 Billable/Specific Code POA Exempt
    Type 1 Excludes
    • current nicotine dependence (F17.2-)
    Z87.891
    )
  • occupational exposure to environmental tobacco smoke (
    ICD-10-CM Diagnosis Code Z57.31

    Occupational exposure to environmental tobacco smoke

      2016 2017 2018 2019 2020 Billable/Specific Code POA Exempt
    Type 2 Excludes
    • exposure to environmental tobacco smoke (Z77.22)
    Z57.31
    )
  • status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility (
    ICD-10-CM Diagnosis Code Z92.82

    Status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility

      2016 2017 2018 2019 2020 Billable/Specific Code POA Exempt
    Code First
    • condition requiring tPA administration, such as:
    • acute cerebral infarction (I63.-)
    • acute myocardial infarction (I21.-, I22.-)
    Z92.82
    )
  • tobacco dependence (
    ICD-10-CM Diagnosis Code F17
    • F17 Nicotine dependence
      • F17.2 Nicotine dependence
        • F17.20 Nicotine dependence, unspecified
          • F17.200 Nicotine dependence, unspecified, uncomplicat...
          • F17.201 Nicotine dependence, unspecified, in remissio...
          • F17.203 Nicotine dependence unspecified, with withdra...
          • F17.208 Nicotine dependence, unspecified, with other ...
          • F17.209 Nicotine dependence, unspecified, with unspec...
        • F17.21 Nicotine dependence, cigarettes
          • F17.210 Nicotine dependence, cigarettes, uncomplicate...
          • F17.211 Nicotine dependence, cigarettes, in remission...
          • F17.213 Nicotine dependence, cigarettes, with withdra...
          • F17.218 Nicotine dependence, cigarettes, with other n...
          • F17.219 Nicotine dependence, cigarettes, with unspeci...
        • F17.22 Nicotine dependence, chewing tobacco
          • F17.220 Nicotine dependence, chewing tobacco, uncompl...
          • F17.221 Nicotine dependence, chewing tobacco, in remi...
          • F17.223 Nicotine dependence, chewing tobacco, with wi...
          • F17.228 Nicotine dependence, chewing tobacco, with ot...
          • F17.229 Nicotine dependence, chewing tobacco, with un...
        • F17.29 Nicotine dependence, other tobacco product
          • F17.290 Nicotine dependence, other tobacco product, u...
          • F17.291 Nicotine dependence, other tobacco product, i...
          • F17.293 Nicotine dependence, other tobacco product, w...
          • F17.298 Nicotine dependence, other tobacco product, w...
          • F17.299 Nicotine dependence, other tobacco product, w...
    F17.-
    )
  • tobacco use (
    ICD-10-CM Diagnosis Code Z72.0

    Tobacco use

      2016 2017 2018 2019 2020 Billable/Specific Code POA Exempt
    Applicable To
    • Tobacco use NOS
    Type 1 Excludes
    • history of tobacco dependence (Z87.891)
    • nicotine dependence (F17.2-)
    • tobacco dependence (F17.2-)
    • tobacco use during pregnancy (O99.33-)
    Z72.0
    )
Type 2 Excludes
Type 2 Excludes Help
A type 2 excludes note represents "not included here". A type 2 excludes note indicates that the condition excluded is not part of the condition it is excluded from but a patient may have both conditions at the same time. When a type 2 excludes note appears under a code it is acceptable to use both the code (I21) and the excluded code together.
  • old myocardial infarction (
    ICD-10-CM Diagnosis Code I25.2

    Old myocardial infarction

      2016 2017 2018 2019 2020 Billable/Specific Code POA Exempt
    Applicable To
    • Healed myocardial infarction
    • Past myocardial infarction diagnosed by ECG or other investigation, but currently presenting no symptoms
    I25.2
    )
  • postmyocardial infarction syndrome (
    ICD-10-CM Diagnosis Code I24.1

    Dressler's syndrome

      2016 2017 2018 2019 2020 Billable/Specific Code
    Applicable To
    • Postmyocardial infarction syndrome
    Type 1 Excludes
    • postinfarction angina (I23.7)
    I24.1
    )
  • subsequent type 1 myocardial infarction (
    ICD-10-CM Diagnosis Code I22
    • I22 Subsequent ST elevation (STEMI) and non-ST el...
      • I22.0 Subsequent ST elevation (STEMI) myocardial in...
      • I22.1 Subsequent ST elevation (STEMI) myocardial in...
      • I22.2 Subsequent non-ST elevation (NSTEMI) myocardi...
      • I22.8 Subsequent ST elevation (STEMI) myocardial in...
      • I22.9 Subsequent ST elevation (STEMI) myocardial in...
    I22.-
    )
Includes
Includes Help
"Includes" further defines, or give examples of, the content of the code or category.
  • 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
The following code(s) above I21 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to I21:
  • I00-I99
    2020 ICD-10-CM Range I00-I99

    Diseases of the circulatory system

    Type 2 Excludes
    • 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.-)
    Diseases of the circulatory system
  • I20-I25
    2020 ICD-10-CM Range I20-I25

    Ischemic heart diseases

    Use Additional
    • code to identify presence of hypertension (I10-I16)
    Ischemic heart diseases
Clinical Information
  • A disorder characterized by gross necrosis of the myocardium; this is due to an interruption of blood supply to the area.
  • Coagulation of blood in any of the coronary vessels. The presence of a blood clot (thrombus) often leads to myocardial infarction.
  • Complete blockage of blood flow through one of the coronary arteries, usually from coronary atherosclerosis.
  • Each year over a million people in the United States Have a heart attack. About half of them die. Many people have permanent heart damage or die because they don't get help immediately. It's important to know the symptoms of a heart attack and call 9-1-1 if someone is having them. Those symptoms include
    • chest discomfort - pressure, squeezing, or pain
    • shortness of breath
    • discomfort in the upper body - arms, shoulder, neck, back
    • nausea, vomiting, dizziness, lightheadedness, sweating
    these symptoms can sometimes be different in women.what exactly is a heart attack? most heart attacks happen when a clot in the coronary artery blocks the supply of blood and oxygen to the heart. Often this leads to an irregular heartbeat - called an arrhythmia - that causes a severe decrease in the pumping function of the heart. A blockage that is not treated within a few hours causes the affected heart muscle to die.
  • Gross necrosis of the myocardium, as a result of interruption of the blood supply to the area, as in coronary thrombosis.
  • Gross necrosis of the myocardium, as a result of interruption of the blood supply to the area.
  • Necrosis of the myocardium caused by an obstruction of the blood supply to the heart (coronary circulation).
  • Necrosis of the myocardium, as a result of interruption of the blood supply to the area. It is characterized by a severe and rapid onset of symptoms that may include chest pain, often radiating to the left arm and left side of the neck, dyspnea, sweating, and palpitations.
Code History
  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): Revised code
    • New description: Acute myocardial infarction
    • 2017 description: ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
Code annotations containing back-references to I21:
  • Code First: Z92.82
    ICD-10-CM Diagnosis Code Z92.82

    Status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility

      2016 2017 2018 2019 2020 Billable/Specific Code POA Exempt
    Code First
    • condition requiring tPA administration, such as:
    • acute cerebral infarction (I63.-)
    • acute myocardial infarction (I21.-, I22.-)
ICD-10-CM Codes Adjacent To I21
I15.9 Secondary hypertension, unspecified
I16 Hypertensive crisis
I16.0 Hypertensive urgency
I16.1 Hypertensive emergency
I16.9 Hypertensive crisis, unspecified
I20 Angina pectoris
I20.0 Unstable angina
I20.1 Angina pectoris with documented spasm
I20.8 Other forms of angina pectoris
I20.9 Angina pectoris, unspecified
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

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.