Excludes1 pair
I09.0 vs I51.4
I09.0 and I51.4 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.
The official note, declared on I09.0
myocarditis not specified as rheumatic (I51.4)
I09.0
Rheumatic myocarditis
Billable
- Chapter 9
- Diseases of the circulatory system
- Section
- I05-I09
Indexed under
- Cardiomyopathy › rheumatic
- Myocarditis › rheumatic (chronic) (inactive) (with chorea)
- Rheumatic › degeneration, myocardium
- Rheumatic › myocarditis (chronic) (inactive) (with chorea)
- Degeneration, degenerative › myocardial, myocardium › with rheumatic fever (conditions in I00)
I51.4
Myocarditis, unspecified
BillableUnspecified
- Chapter 9
- Diseases of the circulatory system
- Section
- I30-I5A
Use when the record says
- Chronic (interstitial) myocarditis
- Myocardial fibrosis
- Myocarditis NOS
Indexed under
- Acardiotrophia
- Myocarditis (with arteriosclerosis)(chronic)(fibroid) (interstitial) (old) (progressive) (senile)
- Arteriosclerosis, arteriosclerotic › myocarditis
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027