ICD-10-CM 2027 diagnosis code
I09.0Rheumatic myocarditis
I09.0 is a valid, billable ICD-10-CM code for rheumatic myocarditis. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.
Looking up by condition? See ICD-10 code for Rheumatic myocarditis, ICD-10 code for Myocarditis rheumatic.
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About I09.0
I09.0 is the ICD-10-CM diagnosis code for rheumatic myocarditis. It belongs to category I09 (other rheumatic heart diseases), block I05-I09 (chronic rheumatic heart diseases) and chapter 9 (diseases of the circulatory system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
Within I09 (other rheumatic heart diseases), I09.0 is specifically for rheumatic myocarditis. Related codes cover rheumatic diseases of endocardium, valve unspecified (I09.1), chronic rheumatic pericarditis (I09.2), other specified rheumatic heart diseases (I09.8) and rheumatic heart disease, unspecified (I09.9).
Don't report I09.0 together with the conditions in its Excludes1 note: myocarditis not specified as rheumatic (I51.4).
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
In MS-DRG v44.0, it is part of the grouping logic for DRG 314 (Other Circulatory System Diagnoses with MCC, relative weight 2.0873), DRG 315 (Other Circulatory System Diagnoses with CC, relative weight 0.9508) and DRG 316 (Other Circulatory System Diagnoses without CC/MCC, relative weight 0.6677), in MDC 05 (Diseases and Disorders of the Circulatory System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Before ICD-10, this condition was coded in ICD-9-CM as 398.0 (rheumatic myocarditis).
Coding notes
- myocarditis not specified as rheumatic (I51.4)
Notes that apply from higher levels
Instructions written at a parent level also apply to I09.0.
Broader instructions also apply from Chapter 9: Diseases of the circulatory system.
Alphabetic index entries
12 entriesTerms in the official ICD-10-CM index that lead to I09.0.
- Cardiomyopathy (familial) (idiopathic) › rheumatic
- Degeneration, degenerative › myocardial, myocardium (fatty) (hyaline) (senile) › with rheumatic fever (conditions in I00)
- Degeneration, degenerative › myocardial, myocardium (fatty) (hyaline) (senile) › with rheumatic fever (conditions in I00) › inactive or quiescent (with chorea)
- Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor) › rheumatic (active) (acute) (chronic) (subacute) › inactive or quiescent with › myocarditis, myocardial degeneration (conditions in I51.4)
- Insufficiency, insufficient › myocardial, myocardium (with arteriosclerosis) › with › rheumatic fever (conditions in I00)
- Insufficiency, insufficient › myocardial, myocardium (with arteriosclerosis) › with › rheumatic fever (conditions in I00) › inactive or quiescent (with chorea)
- Insufficiency, insufficient › myocardial, myocardium (with arteriosclerosis) › rheumatic
- Myocarditis (with arteriosclerosis)(chronic)(fibroid) (interstitial) (old) (progressive) (senile) › with › rheumatic fever (conditions in I00)
- Myocarditis (with arteriosclerosis)(chronic)(fibroid) (interstitial) (old) (progressive) (senile) › with › rheumatic fever (conditions in I00) › inactive or quiescent (with chorea)
- Myocarditis (with arteriosclerosis)(chronic)(fibroid) (interstitial) (old) (progressive) (senile) › rheumatic (chronic) (inactive) (with chorea)
- Rheumatic (acute) (subacute) › degeneration, myocardium
- Rheumatic (acute) (subacute) › myocarditis (chronic) (inactive) (with chorea)
MS-DRG v44.0 grouping
All DRGs →Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.
MDC 05 · Diseases and Disorders of the Circulatory System
ICD-9-CM equivalent
Converter →- 398.0Rheumatic myocarditisexact
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about I09.0
Is I09.0 billable?
- Yes. I09.0 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can I09.0 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict I09.0 as a principal diagnosis.
Is I09.0 a CC or MCC?
- I09.0 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.
What DRG does I09.0 group to?
- I09.0 is used in the MS-DRG v44.0 logic for MS-DRG 314 (Other Circulatory System Diagnoses with MCC), MS-DRG 315 (Other Circulatory System Diagnoses with CC) and MS-DRG 316 (Other Circulatory System Diagnoses without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.
What is the ICD-9 code for I09.0?
- The CMS General Equivalence Mappings map I09.0 to ICD-9-CM 398.0.