I40 – Acute myocarditis
ICD-10-CM 2027 diagnosis code · Other forms of heart disease
ICD-10-CM code
I40
- Code
I40(claims format:I40)- Description
- Acute myocarditis
- Billable
- No – use a more specific code below
- Valid for
- Dates of service October 1, 2026 – September 30, 2027 (FY2027)
- Chapter
- 9. Diseases of the circulatory system (I00-I99)
- Block
- I30-I5A Other forms of heart disease
Billable codes under I40
I40 is a header code and cannot be used on claims. Choose the most specific code:
- I40.0 – Infective myocarditisBillable
- I40.1 – Isolated myocarditisBillable
- I40.8 – Other acute myocarditisBillable
- I40.9 – Acute myocarditis, unspecifiedBillable
Notes for I40
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, in the block I30-I5A (Other forms of heart disease).
Is I40 a billable code?
No. I40 is a header code with more specific child codes; report one of the billable codes listed above.
Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.