Excludes1 pair
I24.9 vs I25.9
I24.9 and I25.9 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 distinction is acute vs chronic.
The official note, declared on I24.9
ischemic heart disease (chronic) NOS (I25.9)
I24.9
Acute ischemic heart disease, unspecified
BillableUnspecified
- Chapter 9
- Diseases of the circulatory system
- Section
- I20-I25
Indexed under
- Cyanotic heart disease
- Ischemia, ischemic › heart › acute or with a stated duration of 4 weeks or less
- Ischemia, ischemic › heart › subacute
- Syndrome › coronary › acute NEC
I25.9
Chronic ischemic heart disease, unspecified
BillableUnspecified
- Chapter 9
- Diseases of the circulatory system
- Section
- I20-I25
Use when the record says
- Ischemic heart disease (chronic) NOS
Indexed under
- Deformity › coronary artery (acquired)
- Ischemia, ischemic › heart (chronic or with a stated duration of over 4 weeks)
- Ischemia, ischemic › myocardium, myocardial (chronic or with a stated duration of over 4 weeks)
- Ischemia, ischemic › supply (coronary)
- Deformity › artery NOS › coronary (acquired)
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