2026 ICD-10-CM Diagnosis Code I42.5Other restrictive cardiomyopathy

ICD-10-CM Codes›I00–I99›I30-I5A›I42

ICD-10-CM I42.5
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I42.5 is a billable ICD-10-CM diagnosis code for other restrictive cardiomyopathy. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 314 through 316. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Myocarditis and cardiomyopathy.

Code Identity

ICD-10-CM Code
I42.5
Billable Status
Yes — Valid for Submission
Code Describes
Other restrictive cardiomyopathy
Short Description
Other restrictive cardiomyopathy
Same as the full description in the CMS dataset.
Parent Code
I42
Cardiomyopathy

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI30-I5AOther forms of heart disease
CategoryI42Cardiomyopathy
This CodeI42.5Other restrictive cardiomyopathy

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acquired abnormality of right cardiac ventricle
  • Acquired stenosis of subpulmonary area
  • Acquired subpulmonary stenosis associated with functionally univentricular heart
  • Acquired subpulmonary stenosis due to restrictive ventricular defect associated with functionally univentricular heart
  • Cardiomyopathy due to mucopolysaccharidosis
  • Cardiomyopathy due to storage disease
  • Familial cardiomyopathy
  • Familial restrictive cardiomyopathy
  • Functionally univentricular heart
  • Primary idiopathic restrictive cardiomyopathy
  • Primary restrictive cardiomyopathy
  • Restrictive cardiomyopathy
  • Restrictive cardiomyopathy due to mucopolysaccharidosis
  • Restrictive cardiomyopathy secondary to amyloidosis
  • Restrictive cardiomyopathy secondary to endocardial fibroelastosis
  • Restrictive cardiomyopathy secondary to glycogen storage disease
  • Restrictive cardiomyopathy secondary to granulomas
  • Restrictive cardiomyopathy secondary to hemochromatosis
  • Restrictive cardiomyopathy secondary to infiltrations
  • Restrictive cardiomyopathy secondary to malignancy
  • Restrictive cardiomyopathy secondary to sarcoidosis
  • Restrictive cardiomyopathy without endomyocardial fibrosis
  • Secondary restrictive cardiomyopathy
  • Subpulmonary stenosis

Tabular List NotesGuidance

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

Inclusion Terms

  • Constrictive cardiomyopathy NOS

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.

    • Cardiomyopathy(familial) (idiopathic)
      • constrictive NOS
    • Cardiomyopathy(familial) (idiopathic)
      • restrictive NEC

Clinical ClassificationClinical

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

CCSR CIR005
Myocarditis and cardiomyopathy
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Cardiomyopathy

Cardiomyopathy is the name for diseases of the heart muscle. These diseases enlarge your heart muscle or make it thicker and more rigid than normal. In rare cases, scar tissue replaces the muscle tissue.

Read the full article at MedlinePlus

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

Convert I42.5 to ICD-9-CMHistory

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

ICD-9-CM
425.4 Prim cardiomyopathy NEC
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 I42.5Overview

Is I42.5 (Cardiomyopathy) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other restrictive cardiomyopathy on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does I42.5 group to?

When other restrictive cardiomyopathy is the principal diagnosis on an inpatient stay, it groups to MS-DRG 314, 315, 316, with relative weights from 0.6821 to 2.0852 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of I42.5?

Under the General Equivalence Mappings, other restrictive cardiomyopathy converts to ICD-9-CM 425.4 (prim cardiomyopathy NEC). 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.