Cardiomyopathy (I42) ICD-10-CM
The I42 code range covers cardiomyopathy with 16 ICD-10-CM diagnosis codes. 13 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
Includes
This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
- myocardiopathy
Code First
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
- pre-existing cardiomyopathy complicating pregnancy and puerperium O99.4
Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
Codes in the I42 Range 16 codes · 13 billable
- I42 CardiomyopathyNon-billable
- I42.0 Dilated cardiomyopathyNon-billable
- I42.00 Dilated cardiomyopathy, unspecified New
- I42.01 Familial-genetic dilated cardiomyopathy New
- I42.09 Other dilated cardiomyopathy New
- I42.1 Obstructive hypertrophic cardiomyopathy
- I42.2 Other hypertrophic cardiomyopathy
- I42.3 Endomyocardial (eosinophilic) disease
- I42.4 Endocardial fibroelastosis
- I42.5 Other restrictive cardiomyopathy
- I42.6 Alcoholic cardiomyopathy
- I42.7 Cardiomyopathy due to drug and external agent
- I42.8 Other cardiomyopathiesNon-billable
- I42.81 Arrhythmogenic cardiomyopathy New
- I42.89 Other cardiomyopathies not elsewhere classified New
- I42.9 Cardiomyopathy, unspecified
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the I42 range.
Cardiomyopathies
A group of diseases in which the dominant feature is the involvement of the CARDIAC MUSCLE itself. Cardiomyopathies are classified according to their predominant pathophysiological features (DILATED CARDIOMYOPATHY; HYPERTROPHIC CARDIOMYOPATHY; RESTRICTIVE CARDIOMYOPATHY) or their etiological/pathological factors (CARDIOMYOPATHY, ALCOHOLIC; ENDOCARDIAL FIBROELASTOSIS).
Cardiomyopathy, Alcoholic
Disease of CARDIAC MUSCLE resulting from chronic excessive alcohol consumption. Myocardial damage can be caused by: (1) a toxic effect of alcohol; (2) malnutrition in alcoholics such as THIAMINE DEFICIENCY; or (3) toxic effect of additives in alcoholic beverages such as COBALT. This disease is usually manifested by DYSPNEA and palpitations with CARDIOMEGALY and congestive heart failure (HEART FAILURE).
Cardiomyopathy, Dilated
A form of CARDIAC MUSCLE disease that is characterized by ventricular dilation, VENTRICULAR DYSFUNCTION, and HEART FAILURE. Risk factors include SMOKING; ALCOHOL DRINKING; HYPERTENSION; INFECTION; PREGNANCY; and mutations in the LMNA gene encoding LAMIN TYPE A, a NUCLEAR LAMINA protein.
Endocardial Fibroelastosis
A condition characterized by the thickening of ENDOCARDIUM due to proliferation of fibrous and elastic tissue, usually in the left ventricle leading to impaired cardiac function (CARDIOMYOPATHY, RESTRICTIVE). It is most commonly seen in young children and rarely in adults. It is often associated with congenital heart anomalies (HEART DEFECTS CONGENITAL;) INFECTION; or gene mutation. Defects in the tafazzin protein, encoded by TAZ gene, result in a form of autosomal dominant familial endocardial fibroelastosis.
About the I42 Code Range
Cardiomyopathy is a group of diseases that primarily affect the heart muscle. Its subdivisions distinguish forms by their main features or identified cause.
I42.0 covers dilated cardiomyopathy, with further codes for unspecified, familial-genetic, and other forms. Hypertrophic cardiomyopathy separates into obstructive and other forms. Separate codes identify endomyocardial disease, endocardial fibroelastosis, and other restrictive cardiomyopathy.
Other subdivisions identify alcoholic cardiomyopathy and cardiomyopathy due to a drug or external agent. Other cardiomyopathies separates arrhythmogenic from other forms not elsewhere classified. I42.9 identifies cardiomyopathy without a specified type.
FY 2027 changes: The FY 2027 ICD-10-CM update, effective October 1, 2026, added I42.00, I42.01, I42.09, I42.81 and I42.89 and deleted I42.0 and I42.8.
Questions About This Page
How many billable codes are in the I42 range?
Of the 16 codes in this range, 13 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the I42 range classify?
The range classifies cardiomyopathy. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
