Is ICD-10-CM code I42 billable?

No, I42 (Cardiomyopathy) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code I42 belong to?

I42 belongs to Chapter 9 of the ICD-10-CM tabular list: I00–I99 (Diseases of the Circulatory System).

I42Not billable, use a more specific code below

Cardiomyopathy

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

13 billable codes under I42: all are a CC; 7 map to HCC 227 (Cardiomyopathy/Myocarditis).A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment. An HCC counts toward a Medicare Advantage patient's risk score.

Instructional notes

Includes: conditions that are coded here

myocardiopathy

Excludes2: not included here, code separately if applicable

ischemic cardiomyopathy (I25.5)
peripartum cardiomyopathy (O90.3)
ventricular hypertrophy (I51.7)

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

pre-existing cardiomyopathy complicating pregnancy and puerperium (O99.4)

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.

Hypertension (page 50)
Atherosclerotic Coronary Artery Disease and Angina (page 52)
Intraoperative and Postprocedural Cerebrovascular Accident (page 53)
Sequelae of Cerebrovascular Disease (page 53)
Acute myocardial infarction (AMI) (page 54)

Read Section I.C.9 (page 50)

All codes under I42

I42 can't be used on a claim. Pick a billable code below; grey headings group them.

I42 MS-DRGs

As the principal diagnosis, all 13 billable codes under I42 group to MS-DRG 314, 315, or 316 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

Other codes that refer to I42

Notes on these codes point to I42.

I5A Code First: cardiomyopathy (I42.-)
O90.3 Includes: Conditions in I42.- arising during pregnancy and the puerperium

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.

Code history

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