Alphabetic Index FY2027

I42.7

Cardiomyopathy due to drug and external agent

FY2027Chapter 9: Diseases of the circulatory system/I30–I5A Other forms of heart disease

BillableComplete code, valid to report
Care settingsHome Health Primary · MMTA - Cardiac and CirculatoryHospital CC

I42.7 (also written I427) is a billable ICD-10-CM diagnosis code for cardiomyopathy due to drug and external agent. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 13 codes in category I42 (Cardiomyopathy). The Alphabetic Index lists it under 4 entries. Its coding notes include a Code first instruction, a Use additional code instruction and 13 Excludes2 entries.

Code first

If the underlying condition listed here is present and known, sequence it first.

This code
  • poisoning due to drug or toxin, if applicable (T36-T65 with fifth or sixth character 1-4)
Inherited from I42 Cardiomyopathy
  • pre-existing cardiomyopathy complicating pregnancy and puerperium (O99.4)

Use additional code

Add the listed code as a secondary code, if known.

This code
  • code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Inherited from I42 Cardiomyopathy
  • ischemic cardiomyopathy (I25.5)
  • peripartum cardiomyopathy (O90.3)
  • ventricular hypertrophy (I51.7)
Also from chapter/block level (10 notes)
Inherited from Chapter 9 Diseases of the circulatory system
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
  • systemic connective tissue disorders (M30-M36)
  • transient cerebral ischemic attacks and related syndromes (G45.-)

Care settings

How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.

Home Health Primary

Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Cardiac and Circulatory clinical group.

Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026

Hospital CC

Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 117 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.

Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix C

Includes

Further defines or gives examples of the content of the category.

Inherited from I42 Cardiomyopathy
  • myocardiopathy

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 4 entries