2024 ICD-10-CM Diagnosis Code I40.9

Acute myocarditis, unspecified

ICD-10-CM Code:
I40.9
ICD-10 Code for:
Acute myocarditis, unspecified
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Not chronic
Code Navigator:

Code Classification

  • Diseases of the circulatory system
    (I00–I99)
    • Other forms of heart disease
      (I30-I5A)
      • Acute myocarditis
        (I40)

I40.9 is a billable diagnosis code used to specify a medical diagnosis of acute myocarditis, 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 I40.9 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 myocarditis
  • Interstitial myocarditis
  • Subacute interstitial myocarditis

Clinical Classification

Clinical Information

  • Acute Myocarditis

    the sudden onset of inflammation of heart muscle with myocellular necrosis; this is generally secondary to an infectious cause, and patients often have a recent history of a flu-like illness.
  • Interstitial Myocarditis

    inflammation of the heart characterized by infiltration of the interstitial tissues by inflammatory cells, histiocytes, and the formation of granulomas. giant cells are often present.

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).

Convert I40.9 to ICD-9-CM

  • ICD-9-CM Code: 422.90 - Acute myocarditis NOS

Patient Education


Cardiomyopathy

Cardiomyopathy is the name for diseases of the heart muscle. These diseases enlarge your heart muscle or make it thicker and more rigid than normal. In rare cases, scar tissue replaces the muscle tissue.

Some people live long, healthy lives with cardiomyopathy. Some people don't even realize they have it. In others, however, it can make the heart less able to pump blood through the body. This can cause serious complications, including:

  • Heart failure
  • Abnormal heart rhythms
  • Heart valve problems
  • Sudden cardiac arrest (SCA)

Heart attacks, high blood pressure, infections, and other diseases can all cause cardiomyopathy. Some types of cardiomyopathy run in families. In many people, however, the cause is unknown. Treatment might involve medicines, surgery, other medical procedures, and lifestyle changes.

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
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.