2026 ICD-10-CM Diagnosis Code I51Complications and ill-defined descriptions of heart disease

ICD-10-CM Codes›I00–I99›I30-I5A›I51

ICD-10-CM I51
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I51 is a non-billable ICD-10-CM category code for complications and ill-defined descriptions of heart disease, so it cannot be submitted on claims. Use a more specific code from this category instead, such as I51.0, I51.1, I51.2, and I51.3.

Code Identity

ICD-10-CM Code
I51
Billable Status
No — Non-Billable Category
Code Describes
Complications and ill-defined descriptions of heart disease
Short Description
Complications and ill-defined descriptions of heart disease
Same as the full description in the CMS dataset.
Chapter
I30-I5A
Other forms of heart disease

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI30-I5AOther forms of heart disease
CategoryI51Complications and ill-defined descriptions of heart disease
This CodeI51Complications and ill-defined descriptions of heart disease

Specific Coding for Complications and ill-defined descriptions of heart diseaseOverview

Non-specific codes like I51 require more characters. Use one of these billable codes instead:

  • Use I51.0 for Cardiac septal defect, acquired

  • Use I51.1 for Rupture of chordae tendineae, not elsewhere classified

  • Use I51.2 for Rupture of papillary muscle, not elsewhere classified

  • Use I51.3 for Intracardiac thrombosis, not elsewhere classified

  • Use I51.4 for Myocarditis, unspecified

  • Use I51.5 for Myocardial degeneration

  • Use I51.7 for Cardiomegaly

  • I51.8 for Other ill-defined heart diseases

  • Use I51.81 for Takotsubo syndrome

  • Use I51.89 for Other ill-defined heart diseases

  • Use I51.9 for Heart disease, unspecified

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Type 2 Excludes

  • heart disease specified as rheumatic I00 I09

Patient EducationClinical

Heart Diseases

Heart disease is a general term that includes many types of heart problems. It's a type of cardiovascular disease, which means heart and blood vessel disease.

The full article covers:

  • What is heart disease?
  • What are the types of heart disease?
  • What causes heart diseases?
  • Who is more likely to develop heart diseases?
  • What are the symptoms of heart disease?
  • How are heart diseases diagnosed?
  • What are the treatments for heart disease?
  • Can heart diseases be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About I51Overview

Is I51 (Complications and ill-defined descriptions of heart disease) a billable code?

No. This is a category header that groups the codes for complications and ill-defined descriptions of heart disease, and headers cannot be submitted on claims. Claims for complications and ill-defined descriptions of heart disease need a more specific code from this category, such as I51.0, I51.1, and I51.2.