I51.9 Heart disease, unspecified
The ICD-10-CM code for Heart disease, unspecified is I51.9 (FY2026). It is a billable, claim-ready diagnosis code.
Classification
- Section
- I30-I5A: Other forms of heart disease (I30-I5A)
- Category I51
- 12 codes (10 billable)
- FY2026 Status
- Stable since FY2024
Also Known As
ICD-10-CM Alphabetic Index entries that lead to I51.9:
- Cardiopathy
- Complication (s) (from) (of) › heart
- Disease, diseased › heart (organic)
- Morbus › cordis
- Lesion (s) (nontraumatic) › cardiac
- Dysfunction › ventricular
- Disease, diseased › heart (organic) › cryptogenic
U.S. Hospital Utilization
- An estimated 6,375 U.S. inpatient stays in 2023 included I51.9 among the documented diagnoses.
- 85 stays listed it as the principal diagnosis.
Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.
Official Coding Guidelines
I11 + addl code for I50/I51 heart conditions (incl I50.-, I51.4, I51.89, I51.9)1) Hypertension with Heart Disease Hypertension with heart conditions classified to I50.-, Heart failure, I51.4, Myocarditis, unspecified, I51.89, Other ill-defined heart diseases, and I51.9, Heart disease, unspecified, is assigned to a code from category I11, Hypertensive heart disease. Use additional code(s) from category I50, Heart failure, or I51, Complications and ill-defined descriptions of heart disease, to identify the heart condition.
Code separately if documented unrelated; assign I10 or I15; sequence per encounterThe same heart conditions (I50.-, I51.4-I51.7, I51.89, I51.9) with hypertension are coded separately if the provider has documented they are unrelated to the hypertension. The applicable hypertension code I10, Essential (primary) hypertension, or a code from category I15, Secondary hypertension, should be assigned. Sequence according to the circumstances of the admission/encounter.
Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026