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  6. 2026 ICD-10-CM Code I51.3

2026 ICD-10-CM Diagnosis Code I51.3

Intracardiac thrombosis, not elsewhere classified

ICD-10-CM Code:
I51.3
ICD-10 Code for:
Intracardiac thrombosis, not elsewhere classified
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Chronic
Code Navigator:

I51.3 is a billable diagnosis code used to specify a medical diagnosis of intracardiac thrombosis, not elsewhere classified. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2025 through September 30, 2026.

Code Classification

  • Diseases of the circulatory system
    I00–I99
    • Other forms of heart disease
      I30-I5A
      • Complications and ill-defined descriptions of heart disease
        I51

Approximate Synonyms

The following list of clinical terms are approximate synonyms, alternative descriptions, or common phrases that might be used by patients, healthcare providers, or medical coders to describe the same condition. These synonyms and related diagnosis terms are often used when searching for an ICD-10 code, especially when the exact medical terminology is unclear. Whether you're looking for lay terms, similar diagnosis names, or common language alternatives, this list can help guide you to the correct ICD-10 classification.

  • Arterial obstruction due to nonthrombotic embolism from heart
  • Arterial obstruction due to thrombotic embolism from mural thrombus of heart
  • Atrial thrombosis
  • Atrial thrombosis
  • Atrial thrombosis
  • Disorder of left atrium as complication of procedure
  • Disorder of right atrium as complication of procedure
  • Intracardiac thrombosis in low output state
  • Left ventricular thrombus
  • Mural thrombus of atrium of heart
  • Mural thrombus of heart
  • Mural thrombus of left atrium
  • Mural thrombus of left ventricle
  • Mural thrombus of right atrium
  • Mural thrombus of right ventricle
  • Mural thrombus of ventricle of heart
  • Occlusion of cutaneous microvasculature structure by cardiac embolus
  • Occlusion of microvasculature of skin caused by embolus
  • Post-infarction mural thrombus
  • Right ventricular thrombus
  • Thromboembolism due to mural thrombus
  • Thrombotic embolism from cardiac atrium
  • Thrombotic embolism from cardiac ventricle
  • Thrombus of cardiac chamber
  • Thrombus of left atrium
  • Thrombus of left atrium
  • Thrombus of physiologic left atrium as complication of procedure
  • Thrombus of physiologic right atrium as complication of procedure
  • Thrombus of right atrium
  • Thrombus of right atrium

Clinical Classification

Clinical Classifications group individual ICD-10-CM diagnosis codes into broader, clinically meaningful categories. These categories help simplify complex data by organizing related conditions under common clinical themes.

They are especially useful for data analysis, reporting, and clinical decision-making. Even when diagnosis codes differ, similar conditions can be grouped together based on their clinical relevance. Each category is assigned a unique CCSR code that represents a specific clinical concept, often tied to a body system or medical specialty.

Other and ill-defined heart disease

CCSR Code: CIR015

Inpatient Default: Y - Yes, default inpatient assignment for principal diagnosis or first-listed diagnosis.

Outpatient Default: Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.

Tabular List of Diseases and Injuries

The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.


Inclusion Terms

Inclusion Terms
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
  • Apical thrombosis (old)
  • Atrial thrombosis (old)
  • Auricular thrombosis (old)
  • Mural thrombosis (old)
  • Ventricular thrombosis (old)

Type 1 Excludes

Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
  • intracardiac thrombosis as current complication following acute myocardial infarction I23.6

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

Index of External Cause of Injuries

References found for this diagnosis code in the External Cause of Injuries Index:

    • Clot(blood)
      • heart
        • not resulting in infarction
    • Embolism(multiple) (paradoxical)
      • cardiac
        • not resulting in infarction
    • Embolism(multiple) (paradoxical)
      • heart (fatty)
        • not resulting in infarction
    • Ischemia, ischemic
      • myocardium, myocardial (chronic or with a stated duration of over 4 weeks)
        • acute, without myocardial infarction
    • Thrombosis, thrombotic(bland) (multiple) (progressive) (silent) (vessel)
      • atrium, auricular
        • not resulting in infarction
    • Thrombosis, thrombotic(bland) (multiple) (progressive) (silent) (vessel)
      • atrium, auricular
        • old
    • Thrombosis, thrombotic(bland) (multiple) (progressive) (silent) (vessel)
      • cardiac
        • not resulting in infarction
    • Thrombosis, thrombotic(bland) (multiple) (progressive) (silent) (vessel)
      • cardiac
        • old
    • Thrombosis, thrombotic(bland) (multiple) (progressive) (silent) (vessel)
      • endocardial
        • not resulting in infarction
    • Thrombosis, thrombotic(bland) (multiple) (progressive) (silent) (vessel)
      • heart (chamber)
        • not resulting in infarction
    • Thrombosis, thrombotic(bland) (multiple) (progressive) (silent) (vessel)
      • heart (chamber)
        • old
    • Thrombosis, thrombotic(bland) (multiple) (progressive) (silent) (vessel)
      • intracardiac NEC (apical) (atrial) (auricular) (ventricular) (old)
    • Thrombosis, thrombotic(bland) (multiple) (progressive) (silent) (vessel)
      • intramural
        • not resulting in infarction
    • Thrombosis, thrombotic(bland) (multiple) (progressive) (silent) (vessel)
      • intramural
        • old
    • Thrombosis, thrombotic(bland) (multiple) (progressive) (silent) (vessel)
      • mural
        • not resulting in infarction
    • Thrombosis, thrombotic(bland) (multiple) (progressive) (silent) (vessel)
      • mural
        • old
    • Thrombosis, thrombotic(bland) (multiple) (progressive) (silent) (vessel)
      • ventricle
        • old

Convert I51.3 to ICD-9-CM

Below are the ICD-9 codes that most closely match this ICD-10 code, based on the General Equivalence Mappings (GEMs). This ICD-10 to ICD-9 crosswalk tool is helpful for coders who need to reference legacy diagnosis codes for audits, historical claims, or approximate code comparisons.

Ill-defined hrt dis NEC

ICD-9-CM: 429.89

Approximate Flag - The approximate mapping means this ICD-10 code does not have an exact ICD-9 equivalent. The matched code is the closest available option, but it may not fully capture the original diagnosis or clinical intent.

View Conversion

Patient Education


Coronary Artery Disease

Coronary artery disease (CAD) is the most common type of heart disease. It is the leading cause of death in the United States in both men and women.

CAD happens when the arteries that supply blood to heart muscle become hardened and narrowed. This is due to the buildup of cholesterol and other material, called plaque, on their inner walls. This buildup is called atherosclerosis. As it grows, less blood can flow through the arteries. As a result, the heart muscle can't get the blood or oxygen it needs. This can lead to chest pain (angina) or a heart attack. Most heart attacks happen when a blood clot suddenly cuts off the hearts' blood supply, causing permanent heart damage.

Over time, CAD can also weaken the heart muscle and contribute to heart failure and arrhythmias. Heart failure means the heart can't pump blood well to the rest of the body. Arrhythmias are changes in the normal beating rhythm of the heart.

NIH: National Heart, Lung, and Blood Institute


[Learn More in MedlinePlus]

Code History

  • FY 2026 - No Change, effective from 10/1/2025 through 9/30/2026
  • FY 2025 - No Change, effective from 10/1/2024 through 9/30/2025
  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.