Acute myocarditis (I40) ICD-10-CM
The I40 code range covers acute myocarditis with 5 ICD-10-CM diagnosis codes. 4 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
Includes
This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
- subacute myocarditis
Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
- acute rheumatic myocarditis I01.2
Codes in the I40 Range 5 codes · 4 billable
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the I40 range.
Acute Myocarditis
The sudden onset of inflammation of heart muscle with myocellular necrosis; this is generally secondary to an infectious cause, and patients often have a recent history of a flu-like illness.
About the I40 Code Range
Acute myocarditis is sudden inflammation of the heart muscle that causes heart muscle cells to die.
The I40 category separates infective myocarditis (I40.0), isolated myocarditis (I40.1), other acute myocarditis (I40.8), and acute myocarditis with no specified type (I40.9).
Questions About This Page
How many billable codes are in the I40 range?
Of the 5 codes in this range, 4 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the I40 range classify?
The range classifies acute myocarditis. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
