2026 ICD-10-CM Diagnosis Code I09.1Rheumatic diseases of endocardium, valve unspecified
ICD-10-CM Codes›I00–I99›I05-I09›I09
- Billable — Valid for Submission
- Chronic Condition
I09.1 is a billable ICD-10-CM diagnosis code for rheumatic diseases of endocardium, valve unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 306 through 307. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Chronic rheumatic heart disease.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Carditis due to rheumatic fever
- Chronic endocarditis
- Chronic rheumatic carditis
- Chronic rheumatic endocarditis
- Chronic rheumatic valvulitis
- Chronic valvulitis
- Endocarditis associated with another disorder
- Rheumatic disease of heart valve
- Rheumatic heart valve regurgitation
- Rheumatic heart valve stenosis
- Rheumatic heart valve stenosis with insufficiency
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Rheumatic endocarditis (chronic)
- Rheumatic valvulitis (chronic)
Type 1 Excludes
- endocarditis, valve unspecified I38
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
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.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Endocarditis(chronic) (marantic) (nonbacterial) (thrombotic) (valvular)
- with rheumatic fever (conditions in I00)
- inactive or quiescent (with chorea)
- Endocarditis(chronic) (marantic) (nonbacterial) (thrombotic) (valvular)
- rheumatic (chronic) (inactive) (with chorea)
- Fever(inanition) (of unknown origin) (persistent) (with chills) (with rigor)
- rheumatic (active) (acute) (chronic) (subacute)
- inactive or quiescent with
- endocarditis
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Heart Diseases
Heart disease is a general term that includes many types of heart problems. It's a type of cardiovascular disease, which means heart and blood vessel disease.
The full article covers:
- What is heart disease?
- What are the types of heart disease?
- What causes heart diseases?
- Who is more likely to develop heart diseases?
- What are the symptoms of heart disease?
- How are heart diseases diagnosed?
- What are the treatments for heart disease?
- Can heart diseases be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert I09.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About I09.1Overview
Is I09.1 (Other rheumatic heart diseases) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report rheumatic diseases of endocardium, valve unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does I09.1 group to?
When rheumatic diseases of endocardium, valve unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 306, 307, with relative weights from 0.9132 to 1.5758 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of I09.1?
Under the General Equivalence Mappings, rheumatic diseases of endocardium, valve unspecified converts to ICD-9-CM 397.9 (rheum endocarditis NOS). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:
- The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
- The condition places limitations on self-care, independent living, and social interactions.
