I40.9
Acute myocarditis, unspecified
Billable FY2026 2025-10-01 → 2026-09-30
This is the unspecified option. 3 more
specific codes sit alongside it. Worth
checking whether the documentation supports one of them.
Exclusions 11 never code together
I00-I99chapter
Excludes2
- certain conditions originating in the perinatal period (P04-P96)P04-P96
- certain infectious and parasitic diseases (A00-B99)A00-B99
- complications of pregnancy, childbirth and the puerperium (O00-O9A)O00-O9A
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Q00-Q99
- endocrine, nutritional and metabolic diseases (E00-E88)E00-E88
- injury, poisoning and certain other consequences of external causes (S00-T88)S00-T88
- neoplasms (C00-D49)C00-D49
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)R00-R94
- systemic connective tissue disorders (M30-M36)M30-M36
- transient cerebral ischemic attacks and related syndromes (G45.-)G45.-
Excludes1 — never code together. The excluded condition and this one are mutually exclusive.
Excludes2 — not included here, but the patient may have both. Code both when documented.
Instructional notes 1
I40code
Includes
- subacute myocarditis
Index entries leading here 2
Alongside this code 3 same parent — I40
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.