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  6. 2024 ICD-10-CM Code I21.9

2024 ICD-10-CM Diagnosis Code I21.9

Acute myocardial infarction, unspecified

ICD-10-CM Code:
I21.9
ICD-10 Code for:
Acute myocardial infarction, unspecified
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Chronic
Code Navigator:

Code Classification

  • Diseases of the circulatory system
    (I00–I99)
    • Ischemic heart diseases
      (I20-I25)
      • Acute myocardial infarction
        (I21)

I21.9 is a billable diagnosis code used to specify a medical diagnosis of acute myocardial infarction, unspecified. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024.

Unspecified diagnosis codes like I21.9 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Acute anteroapical myocardial infarction
  • Acute anteroseptal myocardial infarction
  • Acute infarction of papillary muscle
  • Acute myocardial infarction
  • Acute myocardial infarction due to left coronary artery occlusion
  • Acute myocardial infarction due to occlusion of circumflex branch of left coronary artery
  • Acute myocardial infarction due to right coronary artery occlusion
  • Acute myocardial infarction during procedure
  • Acute myocardial infarction of anterior wall
  • Acute myocardial infarction of anterior wall involving right ventricle
  • Acute myocardial infarction of anterolateral wall
  • Acute myocardial infarction of apex of heart
  • Acute myocardial infarction of apical-lateral wall
  • Acute myocardial infarction of atrium
  • Acute myocardial infarction of basal-lateral wall
  • Acute myocardial infarction of high lateral wall
  • Acute myocardial infarction of inferior wall
  • Acute myocardial infarction of inferior wall involving right ventricle
  • Acute myocardial infarction of inferolateral wall
  • Acute myocardial infarction of inferolateral wall with posterior extension
  • Acute myocardial infarction of inferoposterior wall
  • Acute myocardial infarction of lateral wall
  • Acute myocardial infarction of posterobasal wall
  • Acute myocardial infarction of posterolateral wall
  • Acute myocardial infarction of right ventricle
  • Acute myocardial infarction of septum
  • Acute posterior myocardial infarction
  • Acute Q wave myocardial infarction
  • Acute widespread myocardial infarction
  • Aneurysm of coronary vessels
  • Aneurysm of coronary vessels
  • Cardiac rupture due to and following acute myocardial infarction
  • Coronary artery embolism
  • Coronary artery perforation
  • Coronary artery rupture
  • Drug-related myocardial necrosis syndrome
  • EKG: myocardial infarction
  • First myocardial infarction
  • Mitral valve regurgitation due to acute myocardial infarction
  • Mitral valve regurgitation due to acute myocardial infarction
  • Mitral valve regurgitation due to acute myocardial infarction with papillary muscle and chordal rupture
  • Mitral valve regurgitation due to acute myocardial infarction without papillary muscle and chordal rupture
  • Mixed myocardial ischemia and infarction
  • Myocardial infarction
  • Myocardial infarction due to atherothrombotic coronary artery disease
  • Myocardial infarction in recovery phase
  • Myocardial infarction with non-obstructive coronary artery
  • Myocardial necrosis
  • New myocardial infarction compared to prior study
  • Perforation of coronary artery co-occurrent and due to aneurysm of coronary artery
  • Pericarditis secondary to acute myocardial infarction
  • Postoperative acute myocardial infarction
  • Postoperative myocardial infarction
  • Pulmonary embolism due to and following acute myocardial infarction
  • Rupture of coronary artery co-occurrent and due to aneurysm of coronary artery
  • Rupture of ventricle due to acute myocardial infarction
  • True posterior myocardial infarction

Clinical Classification

Clinical Information

  • Anterior Wall Myocardial Infarction

    myocardial infarction in which the anterior wall of the heart is involved. anterior wall myocardial infarction is often caused by occlusion of the left anterior descending coronary artery. it can be categorized as anteroseptal or anterolateral wall myocardial infarction.

  • Inferior Wall Myocardial Infarction

    myocardial infarction in which the inferior wall of the heart is involved. it is often caused by occlusion of the right coronary artery.

  • Kounis Syndrome

    a disorder of cardiac function secondary to hypersensitivity reactions. it is characterized by coexistence of acute coronary syndromes and cardiac mast cell and platelet activation. it may be induced by exposure to drugs (e.g., antibiotics, anesthetics, contrast media), food, and environmental triggers (e.g., insect bites and stings, poison ivy).

  • MINOCA

    myocardial infarction in the absence of obstructive coronary artery disease. coronary circulation disruption is due to various other factors such as atherosclerotic plaque and coronary vasospasm.

  • Myocardial Infarction

    necrosis of the myocardium caused by an obstruction of the blood supply to the heart (coronary circulation).

  • Non-ST Elevated Myocardial Infarction

    a myocardial infarction that does not produce elevations in the st segments of the electrocardiogram. st segment elevation of the ecg is often used in determining the treatment protocol (see also st elevation myocardial infarction).

  • Acute Myocardial Infarction

    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.

  • Acute Myocardial Infarction by ECG Finding|ACUTE MYOCARDIAL INFARCTION|Acute Myocardial Infarction|Acute Myocardial Infarction by EKG Finding

    an electrocardiographic finding showing a current of injury with st elevation. no specification is provided for localization. (cdisc)

  • Acute Myocardial Infarction From PCI Complication Type|PCI Acute Angiographic Complication|PCI Acute Angiographic Complication|PCI Acute Angiographic Complication|PCIAAC|PCIAAC

    a description of the complications from a percutaneous coronary intervention procedure that lead to an acute myocardial ischemic event.

  • Acute Myocardial Infarction Type|ACMITYPE|ACMITYPE

    a classification or description of the acute myocardial infarction.

  • Death due to Acute Myocardial Infarction Related to COVID-19|Death due to acute MI

    death by any cardiovascular mechanism (e.g., arrhythmia, sudden death, heart failure (hf), stroke, pulmonary embolus, peripheral arterial disease) less than or equal to 30 days after a myocardial infarction (mi), related to the immediate consequences of the mi, such as progressive hf or recalcitrant arrhythmia in a patient with probable or confirmed acute covid-19.

  • Coronary Artery Perforation

    a dissection that extends through the full thickness of the coronary arterial wall. (acc)

Tabular List of Diseases and Injuries

The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.


Inclusion Terms

Inclusion Terms
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
  • Myocardial infarction (acute) NOS

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

Replacement Code

I219 replaces the following previously assigned ICD-10-CM code(s):

  • I21.3 - ST elevation (STEMI) myocardial infarction of unsp site

Convert I21.9 to ICD-9-CM

  • ICD-9-CM Code: 410.90 - AMI NOS, unspecified
    Approximate Flag - The approximate mapping means there is not an exact match between the ICD-10 and ICD-9 codes and the mapped code is not a precise representation of the original code.
  • ICD-9-CM Code: 410.91 - AMI NOS, initial
    Approximate Flag - The approximate mapping means there is not an exact match between the ICD-10 and ICD-9 codes and the mapped code is not a precise representation of the original code.
  • ICD-9-CM Code: 410.92 - AMI NOS, subsequent
    Approximate Flag - The approximate mapping means there is not an exact match between the ICD-10 and ICD-9 codes and the mapped code is not a precise representation of the original code.

Patient Education


Heart Attack

Each year almost 800,000 Americans have a heart attack. A heart attack happens when blood flow to the heart suddenly becomes blocked. Without the blood coming in, the heart can't get oxygen. If not treated quickly, the heart muscle begins to die. But if you do get quick treatment, you may be able to prevent or limit damage to the heart muscle. That's why it's important to know the symptoms of a heart attack and call 911 if you or someone else is having them. You should call, even if you are not sure that it is a heart attack.

The most common symptoms in men and women are:

  • Chest discomfort. It is often in center or left side of the chest. It usually lasts more than a few minutes. It may go away and come back. It can feel like pressure, squeezing, fullness, or pain. It also can feel like heartburn or indigestion.
  • Shortness of breath. Sometimes this is your only symptom. You may get it before or during the chest discomfort. It can happen when you are resting or doing a little bit of physical activity.
  • Discomfort in the upper body. You may feel pain or discomfort in one or both arms, the back, shoulders, neck, jaw, or upper part of the stomach.

You may also have other symptoms, such as nausea, vomiting, dizziness, and lightheadedness. You may break out in a cold sweat. Sometimes women will have different symptoms then men. For example, they are more likely to feel tired for no reason.

The most common cause of heart attacks is coronary artery disease (CAD). With CAD, there is a buildup of cholesterol and other material, called plaque, on their inner walls or the arteries. This is atherosclerosis. It can build up for years. Eventually an area of plaque can rupture (break open). A blood clot can form around the plaque and block the artery.

A less common cause of heart attack is a severe spasm (tightening) of a coronary artery. The spasm cuts off blood flow through the artery.

At the hospital, health care providers make a diagnosis based on your symptoms, blood tests, and different heart health tests. Treatments may include medicines and medical procedures such as coronary angioplasty. After a heart attack, cardiac rehabilitation and lifestyle changes can help you recover.

NIH: National Heart, Lung, and Blood Institute


[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.