ICD-10-CM 2027
ICD-10 code for toxic myocarditis
From the official ICD-10-CM alphabetic index entry “Myocarditis (with arteriosclerosis)(chronic)(fibroid) (interstitial) (old) (progressive) (senile) › toxic”. Page updated September 29, 2026.
About coding toxic myocarditis
The ICD-10-CM code for toxic myocarditis is I40.8 (Other acute myocarditis).
Within I40, choose I40.8 (Other acute myocarditis) only when documentation doesn't support a more specific option: infective myocarditis (I40.0), isolated myocarditis (I40.1) and unspecified (I40.9).
As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" 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), DRG 316 (Other Circulatory System Diagnoses without CC/MCC, relative weight 0.6677), DRG 974 (HIV with Major Related Condition with MCC, relative weight 3.0506), DRG 975 (HIV with Major Related Condition with CC, relative weight 1.3252) and DRG 976 (HIV with Major Related Condition without CC/MCC, relative weight 0.8124), in MDC 05 (Diseases and Disorders of the Circulatory System) and MDC 25 (Human Immunodeficiency Virus Infections), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific toxic myocarditis codes (official index)
- rheumatic
Common questions about toxic myocarditis ICD-10 codes
What is the ICD-10 code for toxic myocarditis?
- I40.8 — Other acute myocarditis.
Is I40.8 billable?
- Yes. I40.8 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can I40.8 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict I40.8 as a principal diagnosis.
Is I40.8 a CC or MCC?
- I40.8 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.