2026 ICD-10-CM Diagnosis Code I01.9Acute rheumatic heart disease, unspecified
ICD-10-CM Codes›I00–I99›I00-I02›I01
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Chronic Condition
I01.9 is a billable ICD-10-CM diagnosis code for acute rheumatic heart disease, unspecified. 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 34 closely related codes. Coders also document this condition as acute rheumatic carditis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Acute rheumatic heart disease and Endocarditis and endocardial disease.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acute rheumatic carditis
- Acute rheumatic fever
- Acute rheumatic heart disease
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Any condition in I00
- Rheumatic carditis, acute
- Rheumatic heart disease, active or acute
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.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Disease, diseased See Also: Syndrome;
Syndrome See Also: Disease;
Bouillaud's I01.9
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Heart Valve Diseases
Heart valve disease happens when one or more of your heart valves don't work well.
The full article covers:
- What are heart valve diseases?
- What are the types of heart valve diseases?
- What causes heart valve diseases?
- Who is more likely to develop heart valve diseases?
- What are the symptoms of heart valve diseases?
- What other problems can heart valve diseases cause?
- How is heart valve disease diagnosed?
- What are the treatments for heart valve diseases?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert I01.9 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About I01.9Overview
What is the ICD-10 code for acute rheumatic heart disease, unspecified?
The ICD-10-CM code for acute rheumatic heart disease, unspecified is I01.9 (sometimes written as I019). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is I01.9 (Rheumatic fever with heart involvement) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report acute rheumatic heart disease, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does I01.9 group to?
When acute rheumatic heart disease, unspecified 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 I01.9 a CC or MCC?
CMS lists I01.9 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 34 closely related codes in its exclusion list.
What is the ICD-9 equivalent of I01.9?
Under the General Equivalence Mappings, acute rheumatic heart disease, unspecified converts to ICD-9-CM 391.9 (ac rheumat hrt dis NOS). The mapping is a direct match.
