2025 ICD-10-CM Diagnosis Code I25.9

Chronic ischemic heart disease, unspecified

ICD-10-CM Code:
I25.9
ICD-10 Code for:
Chronic ischemic heart disease, unspecified
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Chronic
Code Navigator:

I25.9 is a billable diagnosis code used to specify a medical diagnosis of chronic ischemic heart disease, unspecified. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2024 through September 30, 2025.

The code is commonly used in cardiology medical specialties to specify clinical concepts such as selected atherosclerosis, ischemia, and infarction.

Unspecified diagnosis codes like I25.9 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Code Classification

  • Diseases of the circulatory system
    I00–I99
    • Ischemic heart diseases
      I20-I25
      • Chronic ischemic heart disease
        I25

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.

  • Anterior myocardial ischemia
  • Anteroapical myocardial ischemia
  • Anterolateral myocardial ischemia
  • Anteroseptal myocardial ischemia
  • Apical myocardial ischemia
  • Chronic ischemic heart disease
  • Chronic myocardial ischemia
  • Decreased myocardial ischemia compared to prior study
  • EKG myocardial ischemia
  • EKG myocardial ischemia
  • EKG: inferior ischemia
  • Hibernating myocardium
  • Increased myocardial ischemia compared to prior study
  • Inferior myocardial ischemia
  • Inferolateral myocardial ischemia
  • Inferolateral myocardial ischemia with posterior extension
  • Ischemic heart disease
  • Ischemic myocardial dysfunction
  • Lateral myocardial ischemia
  • Mixed myocardial ischemia and infarction
  • Myocardial ischemia
  • Myocardial ischemia manifest on stress test status post myocardial infarction
  • Myocardial ischemia of ventricular septum
  • New myocardial ischemia compared to prior study
  • Posterior myocardial ischemia
  • Posterolateral myocardial ischemia
  • Resting ischemia
  • Stunned myocardium

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.

Coronary atherosclerosis and other heart disease

CCSR Code: CIR011

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.

Clinical Information

  • Myocardial Ischemia

    a disorder of cardiac function caused by insufficient blood flow to the muscle tissue of the heart. the decreased blood flow may be due to narrowing of the coronary arteries (coronary artery disease), to obstruction by a thrombus (coronary thrombosis), or less commonly, to diffuse narrowing of arterioles and other small vessels within the heart. severe interruption of the blood supply to the myocardial tissue may result in necrosis of cardiac muscle (myocardial infarction).

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.
  • Ischemic heart disease (chronic) NOS

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).

Convert I25.9 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.

Chr ischemic hrt dis NEC

ICD-9-CM: 414.8

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.

Chr ischemic hrt dis NOS

ICD-9-CM: 414.9

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.

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 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.