I51.4 Myocarditis, unspecified

Billable ICD-10-CM code, FY2026.

Applicable to

• Chronic (interstitial) myocarditis
• Myocardial fibrosis
• Myocarditis NOS

Excludes1 (never code together)

• acute or subacute myocarditis (I40.-)

Applies from I51 Complications and ill-defined descriptions of heart disease

Excludes2 (not included here)

• heart disease specified as rheumatic (I00-I09)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 227 — Cardiomyopathy/Myocarditis
• CMS-HCC V22: HCC 85 — Congestive Heart Failure
• RxHCC V08: HCC 186 — Heart Failure
• ESRD V24: HCC 85

MS-DRG index

Defines the logic of DRG(s) 314-316 in MDC 05.

Approximate ICD-9-CM (GEMs)

• 429.0 Myocarditis, unspecified

Code annotations containing back-references to I51.4

Back-references to I51.4

• Type 1 Excludes: I09.0 Rheumatic myocarditis ("myocarditis not specified as rheumatic (I51.4)")

Diagnosis Index entries for I51.4

• Acardiotrophia
• Arteriosclerosis, arteriosclerotic (diffuse) (obliterans) (of) (senile) (with calcification) › myocarditis
• Myocarditis (with arteriosclerosis)(chronic)(fibroid) (interstitial) (old) (progressive) (senile)

Nearby codes

• I51 Complications and ill-defined descriptions of heart disease
• I51.0 Cardiac septal defect, acquired
• I51.1 Rupture of chordae tendineae, not elsewhere classified
• I51.2 Rupture of papillary muscle, not elsewhere classified
• I51.3 Intracardiac thrombosis, not elsewhere classified
• I51.4 Myocarditis, unspecified (this code)
• I51.5 Myocardial degeneration
• I51.7 Cardiomegaly
• I51.8 Other ill-defined heart diseases
• I51.81 Takotsubo syndrome
• I51.89 Other ill-defined heart diseases