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ICD10BillableValid for clinical use

ICD-10 Code I40.9: Acute myocarditis, unspecified

I40.9 is a billable ICD-10 diagnosis code used to classify Acute myocarditis, unspecified in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. 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).

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 acute 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
I40Acute myocarditis
currentI40

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

Coverage-related procedures and services

CPT 93319high
3D ECHOCARDIOGRAPHIC IMAGING AND POSTPROCESSING DURING TRANSESOPHAGEAL ECHOCARDIOGRAPHY, OR DURING TRANSTHORACIC ECHOCARDIOGRAPHY FOR CONGENITAL CARDIAC ANOMALIES, FOR THE ASSESSMENT OF CARDIAC STRUCTURE(S) (EG, CARDIAC CHAMBERS AND VALVES, LEFT ATRIAL APPENDAGE, INTERATRIAL SEPTUM, INTERVENTRICULAR SEPTUM) AND FUNCTION, WHEN PERFORMED (LIST SEPARATELY IN ADDITION TO CODE 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 75716high
ANGIOGRAPHY, EXTREMITY, BILATERAL, RADIOLOGICAL SUPERVISION AND INTERPRETATION
Source: CMS coverage guidance
CPT 75710high
ANGIOGRAPHY, EXTREMITY, UNILATERAL, RADIOLOGICAL SUPERVISION AND INTERPRETATION
Source: CMS coverage guidance
CPT 75705high
ANGIOGRAPHY, SPINAL, SELECTIVE, RADIOLOGICAL SUPERVISION AND INTERPRETATION
Source: CMS coverage guidance

Coding guidelines

Compatibility

Legacy and official ICD code match exactly.
Legacy codes
I40.9

Common synonyms

Acute myocarditis, unspecifiedAcute myocarditis

Frequently asked questions

Code details

CodeI40.9
SystemICD10
Display nameAcute myocarditis, unspecified
ChapterDiseases of the circulatory system (I00-I99)
BlockOther forms of heart disease

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

Index terms

Matched terms
Myocarditis(with arteriosclerosis)(chronic)(fibroid) (interstitial) (old) (progressive) (senile)Myocarditis(with arteriosclerosis)(chronic)(fibroid) (interstitial) (old) (progressive) (senile)Myocarditis(with arteriosclerosis)(chronic)(fibroid) (interstitial) (old) (progressive) (senile)Myocarditis(with arteriosclerosis)(chronic)(fibroid) (interstitial) (old) (progressive) (senile)Rupture, ruptured

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.