ICD-10-CM I40.9 is the diagnosis code for Acute myocarditis, unspecified. This code falls under the section "Other forms of heart disease" within Chapter 9 — Diseases of the circulatory system (I00-I99). It is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
Always refer to the official ICD-10-CM Tabular List for complete coding guidelines. Ensure documentation supports the specificity of the code selected. When in doubt, consult a certified medical coder or the latest CMS guidelines.
Understanding where I40.9 sits in the ICD-10-CM classification helps ensure proper coding:
Yes, I40.9 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
I40.9 is the ICD-10-CM diagnosis code for "Acute myocarditis, unspecified". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
The parent code of I40.9 is I40 ("Acute myocarditis"). I40.9 provides a more specific classification within this category.
I40.9 is located in Section I30-I5A — "Other forms of heart disease" within Chapter 9 of the ICD-10-CM Tabular List.
Use I40.9 when the patients documented diagnosis matches "Acute myocarditis, unspecified" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Acute myocarditis, unspecified is I40.9.
Yes, I40.9 can be used as a primary diagnosis code since it is billable and specific.
I40.9 is in Chapter 9 of the ICD-10-CM Tabular List.
Yes, I40.9 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.