I40.9 – Acute myocarditis, unspecified
ICD-10-CM 2027 diagnosis code · Other forms of heart disease
ICD-10-CM code
I40.9
- Code
I40.9(claims format:I409)- Description
- Acute myocarditis, unspecified
- Billable
- Yes – valid for HIPAA-covered transactions
- 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
- Parent codes
- I40
Notes inherited from parent codes
Instructional notes at a category or block level apply to every code below it.
I40 – Acute myocarditis
Includes:
- subacute myocarditis
Excludes1 (not coded here):
- acute rheumatic myocarditis (I01.2)
Index terms for I40.9
Entries in the ICD-10-CM alphabetic index that lead to this code:
Related codes in I40
- I40.0 – Infective myocarditisBillable
- I40.1 – Isolated myocarditisBillable
- I40.8 – Other acute myocarditisBillable
Frequently asked questions
What is ICD-10 code I40.9?
I40.9 is the ICD-10-CM code for acute myocarditis, unspecified, in the block I30-I5A (Other forms of heart disease).
Is I40.9 a billable code?
Yes. I40.9 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.
What category does I40.9 belong to?
It belongs to category I40 – Acute myocarditis.
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.