ICD10BillableValid for clinical use
ICD-10 Code I51.4: Myocarditis, unspecified
Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026
What is this code?
ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the circulatory system (I00-I99).
When is it used?
- May be used when a clinician documents myocarditis, unspecified in a patient's medical record.
- May appear in hospital records, claims, referrals, and clinical documentation.
- This code can be used as a clinically usable diagnosis entry in standardized coding workflows.
What it does not mean
- A code alone does not explain severity, treatment plan, or outcome.
- A medical code should not be treated as a substitute for a doctor's diagnosis or advice.
Code hierarchy
chapter
9Diseases of the circulatory system (I00-I99)
block
I30-I5AOther forms of heart disease
category
I51Complications and ill-defined descriptions of heart disease
currentI51
Official coding notes
Inclusion terms
- Chronic (interstitial) myocarditis
- Myocardial fibrosis
- Myocarditis NOS
Excludes1 (do not code together)
- acute or subacute myocarditis (I40.-)
Where you may see this code
You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.
Related specialists
CardiologistGeneral Physician
Related codes
I51.0Cardiac septal defect, acquiredcodeI51.1Rupture of chordae tendineae, not elsewhere classifiedcodeI51.2Rupture of papillary muscle, not elsewhere classifiedcodeI51.3Intracardiac thrombosis, not elsewhere classifiedcodeI51.5Myocardial degenerationcodeI51.7CardiomegalycodeI51.8Other ill-defined heart diseasescategoryI51.9Heart disease, unspecifiedcode
Sibling codes
I51.0Cardiac septal defect, acquiredbillableI51.1Rupture of chordae tendineae, not elsewhere classifiedbillableI51.2Rupture of papillary muscle, not elsewhere classifiedbillableI51.3Intracardiac thrombosis, not elsewhere classifiedbillableI51.5Myocardial degenerationbillableI51.7CardiomegalybillableI51.8Other ill-defined heart diseasesI51.9Heart disease, unspecifiedbillable
Coverage-related procedures and services
CPT 93325high
DOPPLER ECHOCARDIOGRAPHY COLOR FLOW VELOCITY MAPPING (LIST SEPARATELY IN ADDITION TO CODES FOR ECHOCARDIOGRAPHY)
Source: CMS coverage guidance
CPT 93320high
DOPPLER ECHOCARDIOGRAPHY, PULSED WAVE AND/OR CONTINUOUS WAVE WITH SPECTRAL DISPLAY (LIST SEPARATELY IN ADDITION TO CODES FOR ECHOCARDIOGRAPHIC IMAGING); COMPLETE
Source: CMS coverage guidance
CPT 93321high
DOPPLER ECHOCARDIOGRAPHY, PULSED WAVE AND/OR CONTINUOUS WAVE WITH SPECTRAL DISPLAY (LIST SEPARATELY IN ADDITION TO CODES FOR ECHOCARDIOGRAPHIC IMAGING); FOLLOW-UP OR LIMITED STUDY (LIST SEPARATELY IN ADDITION TO CODES FOR ECHOCARDIOGRAPHIC IMAGING)
Source: CMS coverage guidance
CPT 76376high
3D RENDERING WITH INTERPRETATION AND REPORTING OF COMPUTED TOMOGRAPHY, MAGNETIC RESONANCE IMAGING, ULTRASOUND, OR OTHER TOMOGRAPHIC MODALITY WITH IMAGE POSTPROCESSING UNDER CONCURRENT SUPERVISION; NOT REQUIRING IMAGE POSTPROCESSING ON AN INDEPENDENT WORKSTATION
Source: CMS coverage guidance
CPT 76377high
3D RENDERING WITH INTERPRETATION AND REPORTING OF COMPUTED TOMOGRAPHY, MAGNETIC RESONANCE IMAGING, ULTRASOUND, OR OTHER TOMOGRAPHIC MODALITY WITH IMAGE POSTPROCESSING UNDER CONCURRENT SUPERVISION; REQUIRING IMAGE POSTPROCESSING ON AN INDEPENDENT WORKSTATION
Source: CMS coverage guidance
CPT 93318high
ECHOCARDIOGRAPHY, TRANSESOPHAGEAL (TEE) FOR MONITORING PURPOSES, INCLUDING PROBE PLACEMENT, REAL TIME 2-DIMENSIONAL IMAGE ACQUISITION AND INTERPRETATION LEADING TO ONGOING (CONTINUOUS) ASSESSMENT OF (DYNAMICALLY CHANGING) CARDIAC PUMPING FUNCTION AND TO THERAPEUTIC MEASURES ON AN IMMEDIATE TIME BASIS
Source: CMS coverage guidance
Mapped diagnoses and classifications
SNOMED_CT 45093008high
Chronic interstitial myocarditis
Source: SNOMED International ICD-10 map
SNOMED_CT 1141832002high
Eosinophil infiltration of myocardium
Source: SNOMED International ICD-10 map
SNOMED_CT 427372006high
Eosinophilic myocarditis
Source: SNOMED International ICD-10 map
SNOMED_CT 488007high
Fibroid myocarditis
Source: SNOMED International ICD-10 map
SNOMED_CT 37925008high
Interstitial myocarditis
Source: SNOMED International ICD-10 map
SNOMED_CT 427443009high
Lymphocytic myocarditis
Source: SNOMED International ICD-10 map
Coding guidelines
Compatibility
Legacy and official ICD code match exactly.
Legacy codes
I51.4
Common synonyms
Myocarditis, unspecifiedMyocarditis
Frequently asked questions
About this content
This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.