2026 ICD-10-CM Diagnosis Code I43Cardiomyopathy in diseases classified elsewhere
ICD-10-CM Codes›I00–I99›I30-I5A›I43
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 227
- Chronic Condition
I43 is a billable ICD-10-CM diagnosis code for cardiomyopathy in diseases classified elsewhere. 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, 791, 793. 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. The code is a manifestation code that cannot be reported as the principal diagnosis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Myocarditis and cardiomyopathy.
For Medicare Advantage risk adjustment, I43 maps to CMS-HCC Category 227 (Cardiomyopathy/Myocarditis) under the V28 model, adding a risk factor of about 0.189 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for I43.
Medicare Risk Adjustment (HCC)Billing
I43 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2026.
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.
- Acromegalic cardiomyopathy
- Cardiac familial non-neuropathic amyloidosis
- Cardiac glycogen phosphorylase kinase deficiency
- Cardiac secondary systemic amyloidosis
- Cardiomyopathy associated with another disorder
- Cardiomyopathy due to connective tissue disease
- Cardiomyopathy due to COVID-19
- Cardiomyopathy due to storage disease
- Cardiomyopathy due to viral infection
- Cardiomyopathy in Duchenne muscular dystrophy
- Cardiomyopathy in Friedreich's ataxia
- Cardiomyopathy in myotonic dystrophy
- Diabetic cardiomyopathy
- Dilated cardiomyopathy due to systemic lupus erythematosus
- Disorder of heart due to systemic lupus erythematosus
- Endomyocardial fibrosis
- Familial cardiomyopathy
- Familial non-neuropathic amyloidosis
- Familial restrictive cardiomyopathy
- Glycogen phosphorylase kinase deficiency
- Glycogen phosphorylase kinase deficiency, autosomal recessive
- Glycogen storage disease with severe cardiomyopathy due to glycogenin deficiency
- Heart disease due to thyrotoxicosis
- Hereditary ATTR amyloidosis
- Infiltrative cardiomyopathy
- Localized hereditary amyloidosis
- Localized hereditary cardiac amyloidosis
- Primary eosinophilic endomyocardial cardiomyopathy
- Primary eosinophilic endomyocardial restrictive cardiomyopathy
- Primary restrictive cardiomyopathy
- Primary triglyceride deposit cardiomyovasculopathy
- Restrictive cardiomyopathy secondary to familial storage disease
- Restrictive cardiomyopathy with endomyocardial fibrosis
- Secondary systemic amyloidosis
- Thyrotoxic cardiomyopathy
- Transthyretin related familial amyloid cardiomyopathy
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Code First
- underlying disease, such as:
- amyloidosis E85
- glycogen storage disease E74.0
- gout M10.0
- thyrotoxicosis E05.0 E05.9
Type 1 Excludes
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.
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Endomyocardial Fibrosis
a condition characterized by the thickening of the ventricular endocardium and subendocardium (myocardium), seen mostly in children and young adults in the tropical climate. the fibrous tissue extends from the apex toward and often involves the heart valves causing restrictive blood flow into the respective ventricles (cardiomyopathy, restrictive).Endomyocardial Fibrosis
a disease characterized by fibrotic thickening of the endocardium, particularly the right and/or left inflow tracts. the disease often involves the atrioventricular valves, leading to valvular regurgitaion. it most commonly occurs in children living within 15 degrees of the equator.Myocardial Degeneration
degeneration of myocardial tissue.
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 I43 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About I43Overview
What is the ICD-10 code for cardiomyopathy in diseases classified elsewhere?
The ICD-10-CM code for cardiomyopathy in diseases classified elsewhere is I43. It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is I43 (Cardiomyopathy in diseases classified elsewhere) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report cardiomyopathy in diseases classified elsewhere on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does I43 group to?
On inpatient claims, cardiomyopathy in diseases classified elsewhere maps to MS-DRG 314, 315, 316, 791, 793, with relative weights from 0.6821 to 4.1696 depending on complications. Higher weights mean higher Medicare reimbursement.
Is I43 a CC or MCC?
CMS lists I43 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.
Can I43 be a principal diagnosis?
No. This is a manifestation code: cardiomyopathy in diseases classified elsewhere describes the manifestation of an underlying disease rather than the disease itself, so the underlying condition is sequenced first.
What HCC is I43?
I43 (cardiomyopathy in diseases classified elsewhere) maps to CMS-HCC Category 227 (Cardiomyopathy/Myocarditis), commonly written as HCC 227, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 85 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 186.
Does I43 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, I43 adds a risk adjustment factor of about 0.189 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.145 to 0.200 depending on the payment segment). A more severe related category (HCC 221, HCC 222, HCC 223, HCC 224, HCC 225, and HCC 226) supersedes it when both are reported. See the full factor table on the HCC 227 category page.
