I40
Non-billableAcute myocarditis
I40 is the ICD-10-CM code for Acute myocarditis. It is a non-billable category code — use a more specific child code such as I40.0 for billing.
- Status
- Header (non-billable)
- Chapter
- I00-I99
- Subcodes
- 4
- Edition
- FY2026
I00-I99 Diseases of the circulatory system
What this means — in plain language
MedlinePlus · NIHCardiomyopathy 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…
Read more about Cardiomyopathy at MedlinePlus ↗Source: U.S. National Library of Medicine (MedlinePlus). Informational only — not medical advice.
Includes
- •subacute myocarditis
Excludes1 — not coded here
- •acute rheumatic myocarditis (I01.2)
Frequently asked questions
- What is ICD-10 code I40?
- I40 is the ICD-10-CM code for "Acute myocarditis". It falls under I00-I99 Diseases of the circulatory system.
- Is I40 a billable code?
- No — I40 is a non-billable header code. Use a more specific child code (such as I40.0) for billing.
- What is excluded from I40?
- Excludes1 (not coded here): acute rheumatic myocarditis (I01.2).
Source: CMS ICD-10-CM FY2026. For informational purposes only — not medical advice. See our medical disclaimer.
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