2026 ICD-10-CM Diagnosis Code I23.4Rupture of chordae tendineae as current complication following acute myocardial infarction

ICD-10-CM Codes›I00–I99›I20-I25›STEMI

ICD-10-CM I23.4
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I23.4 is a billable ICD-10-CM diagnosis code for rupture of chordae tendineae as current complication following acute myocardial infarction. 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. Coders also document this condition as cardiac rupture due to and following acute myocardial infarction. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Complications of acute myocardial infarction.

This medical diagnosis code is frequently used in Cardiology medical specialties to designate conditions such selected atherosclerosis, ischemia, and infarction.

Code Identity

ICD-10-CM Code
I23.4
Billable Status
Yes — Valid for Submission
Code Describes
Rupture of chordae tendineae as current complication following acute myocardial infarction
Short Description
Rupture of chord tendne as current comp following AMI
Parent Code
I23
Certain current complications following ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction (within the 28 day period)

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI20-I25Ischemic heart diseases
CategorySTEMICertain current complications following ST elevation and non-ST elevation (NSTEMI) myocardial infarction (within the 28 day period) (I23)
This CodeI23.4Rupture of chordae tendineae as current complication following acute myocardial infarction

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cardiac rupture due to and following acute myocardial infarction
  • Mitral valve regurgitation due to acute myocardial infarction
  • Mitral valve regurgitation due to acute myocardial infarction with papillary muscle and chordal rupture
  • Rupture of chordae tendinae due to and following acute myocardial infarction
  • Rupture of chordae tendineae

Tabular List NotesGuidance

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

Type 1 Excludes

  • rupture of chordae tendineae not specified as current complication following acute myocardial infarction I51.1

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.

    • Complication(s) (from) (of)
      • following
        • acute myocardial infarction NEC
          • chordae tendinae rupture
    • Complication(s) (from) (of)
      • following
        • acute myocardial infarction NEC
          • rupture
            • chordae tendineae
    • Laceration
      • chordae tendinae NEC
        • following acute myocardial infarction (current complication)
    • Rupture, ruptured
      • chordae tendineae NEC
        • following acute myocardial infarction (current complication)

Clinical ClassificationClinical

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

CCSR CIR010
Complications of acute myocardial infarction
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Heart Attack

Each year almost 800,000 Americans have a heart attack. A heart attack happens when blood flow to the heart suddenly becomes blocked. Without the blood coming in, the heart can't get oxygen. If not treated quickly, the heart muscle begins to die.

Read the full article at MedlinePlus

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

Convert I23.4 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 I23.4Overview

Is I23.4 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report rupture of chordae tendineae as current complication following acute myocardial infarction on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does I23.4 group to?

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

Under the General Equivalence Mappings, rupture of chordae tendineae as current complication following acute myocardial infarction 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.