I51.8Header code — not billable
Other ill-defined heart diseases
- Chapter
- 9. Diseases of the circulatory system
- Category
- I51
- Effective date
- October 1, 2026
Related codes in category I51
I51Complications and ill-defined descriptions of heart diseaseI51.0Cardiac septal defect, acquiredYesI51.1Rupture of chordae tendineae, not elsewhere classifiedYesI51.2Rupture of papillary muscle, not elsewhere classifiedYesI51.3Intracardiac thrombosis, not elsewhere classifiedYesI51.4Myocarditis, unspecifiedYesI51.5Myocardial degenerationYesI51.7CardiomegalyYesI51.81Takotsubo syndromeYesI51.89Other ill-defined heart diseasesYesI51.9Heart disease, unspecifiedYes
Frequently asked questions
What is ICD-10 code I51.8?
I51.8 is an ICD-10-CM diagnosis code for Other ill-defined heart diseases.
Is I51.8 a billable code?
No. I51.8 is a category/header code, not billable on its own — use one of its more specific child codes instead.
What ICD-10-CM chapter is I51.8 in?
I51.8 falls under Chapter 9: Diseases of the circulatory system.
When did I51.8 become effective?
I51.8 has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.
What other codes are related to I51.8?
I51.8 belongs to category I51, which includes 11 other codes — see the related codes list on this page.
ICD-10-CM data maintained by CDC/CMS (public domain). Always verify codes with authoritative sources before making coding or billing decisions.