2026 ICD-10-CM Diagnosis Code I51.1Rupture of chordae tendineae, not elsewhere classified

ICD-10-CM Codes›I00–I99›I30-I5A›I51

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

I51.1 is a billable ICD-10-CM diagnosis code for rupture of chordae tendineae, not elsewhere classified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 306 through 307. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other and ill-defined heart disease.

Code Identity

ICD-10-CM Code
I51.1
Billable Status
Yes — Valid for Submission
Code Describes
Rupture of chordae tendineae, not elsewhere classified
Short Description
Rupture of chordae tendineae, not elsewhere classified
Same as the full description in the CMS dataset.
Parent Code
I51
Complications and ill-defined descriptions 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 CodeI51.1Rupture of chordae tendineae, not elsewhere classified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormality of mitral chordae tendinae
  • Abnormality of right atrioventricular valve chordae tendinae
  • Abnormality of tricuspid chordae tendinae
  • Acute mitral regurgitation
  • Acute mitral regurgitation from chordal rupture
  • Mitral chordae rupture
  • Postprocedural mitral valve regurgitation
  • Postprocedural mitral valve regurgitation due to papillary muscle and chordal rupture
  • Rupture of chordae tendineae
  • Rupture of left atrioventricular valve chordae tendinae
  • Rupture of right atrioventricular valve chordae tendinae
  • Ruptured tricuspid chordae

Tabular List NotesGuidance

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

Type 1 Excludes

  • rupture of chordae tendineae as current complication following acute myocardial infarction I23.4

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Laceration
      • chordae tendinae NEC
    • Rupture, ruptured
      • chordae tendineae NEC

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR CIR015
Other and ill-defined heart disease
Default principal diagnosis: inpatient Yes · outpatient Yes

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.

Convert I51.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
429.5 Chordae tendinae rupture
Approximate The match is approximate rather than exact.

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 I51.1Overview

Is I51.1 (Complications and ill-defined descriptions of heart disease) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report rupture of chordae tendineae, not elsewhere classified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does I51.1 group to?

When rupture of chordae tendineae, not elsewhere classified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 306, 307, with relative weights from 0.9132 to 1.5758 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of I51.1?

Under the General Equivalence Mappings, rupture of chordae tendineae, not elsewhere classified converts to ICD-9-CM 429.5 (chordae tendinae rupture). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.