2026 ICD-10-CM Diagnosis Code I42.2Other hypertrophic cardiomyopathy

ICD-10-CM Codes›I00–I99›I30-I5A›I42

ICD-10-CM I42.2
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I42.2 is a billable ICD-10-CM diagnosis code for other hypertrophic 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
I42.2
Billable Status
Yes — Valid for Submission
Code Describes
Other hypertrophic cardiomyopathy
Short Description
Other hypertrophic 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 CodeI42.2Other hypertrophic cardiomyopathy

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Apical hypertrophic cardiomyopathy
  • Apical hypertrophic cardiomyopathy with aneurysm
  • Cardiomyopathy due to storage disease
  • Cardiomyopathy in Friedreich's ataxia
  • Familial cardiomyopathy
  • Fatal congenital hypertrophic cardiomyopathy due to glycogen storage disease
  • Hypertrophic cardiomyopathy
  • Hypertrophic cardiomyopathy and renal tubular disease due to mitochondrial DNA mutation
  • Hypertrophic cardiomyopathy due to disorder
  • Hypertrophic cardiomyopathy due to Friedreich ataxia
  • Hypertrophic cardiomyopathy due to glycogen storage disease
  • Hypertrophic cardiomyopathy due to hyperthyroidism
  • Hypertrophic cardiomyopathy due to lysosomal disease
  • Hypertrophic cardiomyopathy due to neuromuscular disorder
  • Hypertrophic cardiomyopathy with genetic marker
  • Hypertrophic cardiomyopathy with hypotonia and lactic acidosis syndrome
  • Hypertrophic cardiomyopathy without obstruction
  • Hypertrophic mitochondrial cardiomyopathy
  • Hypertrophic mitochondrial cardiomyopathy associated with cataracts and lactic acidosis
  • Infantile hypertrophic cardiomyopathy due to MRPL44 deficiency
  • Left ventricular aneurysm
  • Mitochondrial hypertrophic cardiomyopathy with lactic acidosis due to MTO1 deficiency
  • Primary familial hypertrophic cardiomyopathy
  • Primary hypertrophic cardiomyopathy
  • Primary idiopathic hypertrophic cardiomyopathy
  • Progressive sensorineural hearing loss and hypertrophic cardiomyopathy syndrome

Tabular List NotesGuidance

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

Inclusion Terms

  • Nonobstructive hypertrophic cardiomyopathy

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)
      • hypertrophic (nonobstructive)
    • Hypertrophy, hypertrophic
      • myocardium
        • idiopathic

Clinical ClassificationClinical

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

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

Clinical InformationClinical

  • Apical Hypertrophic Cardiomyopathy

    a hypertrophic cardiomyopathy characterized by apical hypertrophy, typically left ventricular hypertrophy (described as ace of spades sign), and deep t-wave inversions in ekg. clinical symptoms include minor symptoms such as chest pain; dyspnea; and syncope to more complex symptoms such as atrial fibrillation; ventricular fibrillation; myocardial infarction and congestive heart failure. a transient left ventricular apical hypertrophy is sometimes associated with takotsubo cardiomyopathy.

  • Familial Hypertrophic Cardiomyopathy Type 1|Asymmetric Septal Hypertrophy|CMH1|Hereditary Ventricular Hypertrophy|IHSS|Idiopathic Hypertrophic Subaortic Stenosis

    an autosomal dominant subtype of familial hypertrophic cardiomyopathy caused by mutation(s) in the cav3 gene, myh7 gene, or mylk2 gene encoding caveolin-3, myosin heavy chain 7, and myosin light chain kinase 2, skeletal/cardiac muscle respectively.

  • Familial Hypertrophic Cardiomyopathy Type 11|CMH11

    an autosomal dominant subtype of familial hypertrophic cardiomyopathy caused by mutation(s) in the actc1 gene, encoding actin, alpha cardiac muscle 1.

  • Familial Hypertrophic Cardiomyopathy Type 14|CMH14

    an autosomal dominant subtype of familial hypertrophic cardiomyopathy caused by mutation(s) in the myh6 gene, encoding myosin-6.

  • Familial Hypertrophic Cardiomyopathy Type 17|CMH17

    an autosomal dominant subtype of familial hypertrophic cardiomyopathy caused by mutation(s) in the jph2 gene, encoding junctophilin-2.

  • Familial Hypertrophic Cardiomyopathy Type 2|CMH2

    an autosomal dominant subtype of familial hypertrophic cardiomyopathy caused by mutation(s) in the tnnt2 gene, encoding troponin t, cardiac muscle.

  • Familial Hypertrophic Cardiomyopathy Type 26|CMH26

    an autosomal dominant subtype of familial hypertrophic cardiomyopathy caused by mutation(s) in the flnc gene, encoding filamin-c.

  • Familial Hypertrophic Cardiomyopathy Type 27|CMH27

    an autosomal recessive subtype of familial hypertrophic cardiomyopathy caused by mutation(s) in the alpk3 gene, encoding alpha-protein kinase 3.

  • Familial Hypertrophic Cardiomyopathy Type 3|CMH3

    an autosomal dominant subtype of familial hypertrophic cardiomyopathy caused by mutation(s) in the tpm1 gene, encoding tropomyosin alpha-1 chain.

  • Familial Hypertrophic Cardiomyopathy Type 4|CMH4

    an autosomal dominant condition caused by mutation(s) in the mybpc3 gene, encoding mybpc3 protein. it is characterized by severe neonatal hypertrophic cardiomyopathy.

  • Familial Hypertrophic Cardiomyopathy Type 6|CMH6

    an autosomal dominant subtype of familial hypertrophic cardiomyopathy caused by mutation(s) in the prkag2 gene, encoding 5'-amp-activated protein kinase subunit gamma-2.

  • Familial Hypertrophic Cardiomyopathy Type 7|CMH7

    an autosomal dominant subtype of familial hypertrophic cardiomyopathy caused by mutation(s) in the tnni3 gene, encoding troponin i, cardiac muscle.

  • Familial Hypertrophic Cardiomyopathy|Hypertrophic Familial Cardiomyopathy

    hypertrophic cardiomyopathy caused by mutations in the genes encoding components of the sarcomere, in the absence of predisposing conditions.

  • Hypertrophic Cardiomyopathy

    a condition in which the myocardium is hypertrophied without an obvious cause. the hypertrophy is generally asymmetric and may be associated with obstruction of the ventricular outflow tract.

  • Left Ventricular Aneurysm

    a bulge or ballooning in the wall of the left ventricle of the heart.

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 I42.2 to ICD-9-CMHistory

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

ICD-9-CM
425.18 Oth hyprtrophic cardiomy
Exact Match The mapping is direct, with no qualifiers.

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 I42.2Overview

Is I42.2 (Cardiomyopathy) a billable code?

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

What MS-DRG does I42.2 group to?

When other hypertrophic 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 I42.2?

Under the General Equivalence Mappings, other hypertrophic cardiomyopathy converts to ICD-9-CM 425.18 (oth hyprtrophic cardiomy). The mapping is a direct match.

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.