All ICD10 Codes
I43Billable, valid for claims from October 1, 2026

Cardiomyopathy in diseases classified elsewhere

In Other forms of heart disease (I30-I5A), chapter 9: Diseases of the Circulatory System

  • I43 is billable and valid on claims for FY 2027. If the record has more detail, check the other codes under I30-I5A below.
  • As a secondary diagnosis it is a CC (complication or comorbidity), which can raise the MS-DRG payment. It doesn't count when the principal diagnosis is one of 117 closely related codes.
  • Counts toward HCC 227 (Cardiomyopathy/Myocarditis) in the Medicare Advantage risk model (CMS-HCC V28).
  • AHRQ's Chronic Condition Indicator classes it as chronic: expected to last 12 months or longer and to limit daily life or need ongoing care.
  • Can't be the principal diagnosis: code the underlying condition first. (Manifestation list)

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Instructional notes

Excludes1: not coded here, use a different code

Code first: code the underlying condition first, then this code

  • underlying disease, such as:
  • amyloidosis (E85.-)
  • glycogen storage disease (E74.0-)
  • gout (M10.0-)
  • thyrotoxicosis (E05.0-E05.9-)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Covers hypertension with heart and kidney disease, coronary artery disease with angina, perioperative stroke, cerebrovascular sequelae, and acute myocardial infarction types and timing.

Read Section I.C.9 (page 50)

Other codes under I30-I5A

Other forms of heart disease (I30-I5A)

I43 MS-DRGs

As the principal diagnosis, I43 groups to MS-DRG 314, 315, 316, 791, or 793 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

Related conditions

Grouped by AHRQ's Clinical Classifications Software Refined (CCSR), which sorts every diagnosis code into clinically meaningful categories.

I43 is in Myocarditis and cardiomyopathy (CIR005), with 31 codes. Others in it:

  • A36.81 Diphtheritic cardiomyopathy
  • A38.1 Scarlet fever with myocarditis
  • A39.50 Meningococcal carditis, unspecified
  • A39.52 Meningococcal myocarditis
  • B26.82 Mumps myocarditis
  • B33.20 Viral carditis, unspecified
  • B33.22 Viral myocarditis
  • B33.24 Viral cardiomyopathy

Medicare coverage articles listing I43

These 19 Medicare billing and coding articles list I43 as a diagnosis that supports medical necessity for the services they cover. From the CMS Medicare Coverage Database; check your own contractor's article before billing.

And 9 more.

Other codes that refer to I43

Notes on these codes point to I43.

  • M10 Use Additional Code: Cardiomyopathy in diseases classified elsewhere (I43)
  • M1A Use Additional Code: Cardiomyopathy in diseases classified elsewhere (I43)

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

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 more about cardiomyopathy on MedlinePlus

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.

ICD-9-CM equivalent

Legacy crosswalk from the CMS General Equivalence Mappings (last updated 2018).

  • 425.8 Cardiomyopathy in other diseases classified elsewhere (approximate)
ICD-9 to ICD-10 converter