ICD-10 Code I09.0 – Rheumatic myocarditis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I09.0 – Rheumatic myocarditis
What it is
This code identifies myocarditis caused by rheumatic fever or rheumatic heart disease. Use it when the medical record documents rheumatic inflammation of the heart muscle.
Clinical signs
Clinical features vary; refer to documentation. Findings may include evidence of rheumatic heart involvement with myocardial inflammation, often alongside other rheumatic cardiac manifestations.
When to use this code
Use I09.0 when the provider specifically documents rheumatic myocarditis or rheumatic involvement of the myocardium. It is appropriate when the diagnosis is established in the chart and not merely suspected. If the record only states myocarditis without a rheumatic cause, check documentation.
Do not use for
Do not use this code for nonrheumatic myocarditis or other inflammatory heart disease. Check documentation if the record describes rheumatic fever, valvular disease, or carditis without clear myocardial involvement.
Coding tip
Code I09.0 only when the rheumatic cause is clearly documented; otherwise, verify the exact cardiac diagnosis.