I42.4 vs Q24
I42.4 (Endocardial fibroelastosis) compared with Q24 (Other congenital malformations of heart), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. Q24 carries an Excludes1 note covering I42.4: “endocardial fibroelastosis (I42.4)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| I42.4Endocardial fibroelastosis | Q24Other congenital malformations of heart | |
|---|---|---|
| Billing status | Billable | Non-billable header |
| Classification | I00-I99 — Diseases of the Circulatory System (I00-I99) | Q00-Q99 — Congenital Malformations, Deformations and Chromosomal Abnormalities (Q00-Q99) |
| Definition | Endocardial fibroelastosis is a billable ICD-10-CM diagnosis code (I42.4). | Other congenital malformations of heart is a non-billable ICD-10-CM category code (Q24). |
| Includes | myocardiopathy Congenital cardiomyopathy Elastomyofibrosis | — |
| Code first | pre-existing cardiomyopathy complicating pregnancy and puerperium (O99.4) | — |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources