I23.1 vs I51.0
I23.1 and I51.0 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on I23.1
acquired atrial septal defect not specified as current complication following acute myocardial infarction (I51.0)
I23.1
Atrial septal defect as current complication following acute myocardial infarction
Billable
- Chapter 9
- Diseases of the circulatory system
- Section
- I20-I25
Indexed under
- Defect, defective › atrial septal › following acute myocardial infarction
- Defect, defective › septalNOS › atrial › following acute myocardial infarction
- Complication › following › acute myocardial infarction NEC › atrial › septal defect (s) (from) (of)
- Complication › following › acute myocardial infarction NEC › defect › septal › atrial (s) (from) (of)
I51.0
Cardiac septal defect, acquired
Billable
- Chapter 9
- Diseases of the circulatory system
- Section
- I30-I5A
Use when the record says
- Acquired septal atrial defect (old)
- Acquired septal auricular defect (old)
- Acquired septal ventricular defect (old)
Indexed under
- Defect, defective › septalNOS › 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