ICD-10-CM I40 is the diagnosis code for Acute myocarditis. This code falls under the section "Other forms of heart disease" within Chapter 9 — Diseases of the circulatory system (I00-I99). It is a non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
The following conditions should never be coded at the same time as I40. They are mutually exclusive:
Understanding where I40 sits in the ICD-10-CM classification helps ensure proper coding:
No, I40 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.
I40 is the ICD-10-CM diagnosis code for "Acute myocarditis". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
I40 is located in Section I30-I5A — "Other forms of heart disease" within Chapter 9 of the ICD-10-CM Tabular List.
I40 has 4 sub-code(s) that provide more specific detail: I40.0, I40.1, I40.8, I40.9.
Use I40 when the patients documented diagnosis matches "Acute myocarditis" 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 is I40.
No, I40 is non-billable. Use a more specific sub-code for primary diagnosis billing.
I40 is in Chapter 9 of the ICD-10-CM Tabular List.
Type 1 Excludes for I40 include: acute rheumatic myocarditis (I01.2).
Yes, I40 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.