2026 ICD-10-CM Diagnosis Code I42.7Cardiomyopathy due to drug and external agent
ICD-10-CM Codes›I00–I99›I30-I5A›I42
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Not Chronic
I42.7 is a billable ICD-10-CM diagnosis code for cardiomyopathy due to drug and external agent. 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. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 112 closely related codes. Coders also document this condition as cardiomyopathy caused by drug. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Drug induced or toxic related condition and Myocarditis and cardiomyopathy.
I42.7 no longer risk-adjusts for Medicare Advantage: it mapped to HCC 85 under the retired CMS-HCC V24 model through payment year 2025 but maps to no category in the live V28 model. It still risk-adjusts in the PACE (CMS-HCC V22) category 85, ESRD (V21) category 85, ESRD (V24) category 85, and RxHCC Part D (V08) category 186 for payment year 2026.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
I42.7 no longer risk-adjusts for Medicare Advantage: it maps to no payment category in the live CMS-HCC V28 model, although it still risk-adjusts in the other CMS models shown below.
Source: CMS Payment Year 2026 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Cardiomyopathy caused by drug
- Chronic myocardial disorder caused by chemical or external agent
- Cobalt cardiomyopathy
- Dilated cardiomyopathy caused by drug
- Toxic cardiomyopathy
- Toxic dilated cardiomyopathy
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Code First
Use Additional Code
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.
The “use additional code” indicates that a secondary code could be used to further specify the patient’s condition. This note is not mandatory and is only used if enough information is available to assign an additional code.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Cardiomyopathy (familial) (idiopathic) I42.9
drugs I42.7
external agents NEC I42.7
toxic NEC I42.7
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
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 I42.7 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About I42.7Overview
What is the ICD-10 code for cardiomyopathy due to drug and external agent?
The ICD-10-CM code for cardiomyopathy due to drug and external agent is I42.7 (sometimes written as I427). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is I42.7 (Cardiomyopathy) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report cardiomyopathy due to drug and external agent on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does I42.7 group to?
When cardiomyopathy due to drug and external agent 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.
Is I42.7 a CC or MCC?
CMS lists I42.7 as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 112 closely related codes in its exclusion list.
What is the ICD-9 equivalent of I42.7?
Under the General Equivalence Mappings, cardiomyopathy due to drug and external agent converts to ICD-9-CM 425.9 (second cardiomyopath NOS). The mapping is approximate, so confirm the match fits the documentation.
Does I42.7 risk-adjust for Medicare Advantage payment?
Not for Medicare Advantage. I42.7 mapped to HCC 85 in the retired CMS-HCC V24 model, which last determined payment in 2025, but it maps to no category in the live V28 model; see all codes that no longer risk-adjust. It still risk-adjusts in the PACE (CMS-HCC V22) category 85 (Congestive Heart Failure), ESRD (V21) category 85 (Congestive Heart Failure), ESRD (V24) category 85 (Congestive Heart Failure), and RxHCC Part D (V08) category 186 (Heart Failure).
