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  6. 2025 ICD-10-CM Code I49.9

2025 ICD-10-CM Diagnosis Code I49.9

Cardiac arrhythmia, unspecified

ICD-10-CM Code:
I49.9
ICD-10 Code for:
Cardiac arrhythmia, unspecified
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Chronic
Code Navigator:

I49.9 is a billable diagnosis code used to specify a medical diagnosis of cardiac arrhythmia, 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 cardiac arrhythmias (other).

Unspecified diagnosis codes like I49.9 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
    • Other forms of heart disease
      I30-I5A
      • Other cardiac arrhythmias
        I49

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.

  • Abnormal heart beat
  • Abnormal heart beat
  • Arrhythmia due to and following acute myocardial infarction
  • Arrhythmia due to vegetation of infective endocarditis
  • Atypical Timothy syndrome
  • Cardiac arrhythmia
  • Cardiac arrhythmia associated with genetic disorder
  • Cardiac arrhythmia due to coronary artery spasm
  • Cardiac arrhythmia during pregnancy
  • Cardiac arrhythmia during pregnancy
  • Cardiac arrhythmia in mother complicating childbirth
  • Cardiac channelopathy
  • EKG: ventricular arrhythmia
  • Fibrillation
  • Finding of regularity of heart rhythm
  • Finding of regularity of heart rhythm
  • GNB5-related intellectual disability, cardiac arrhythmia syndrome
  • Heart disease in mother complicating childbirth
  • Heart disease in mother complicating pregnancy, childbirth AND/OR puerperium
  • Heart irregularly irregular
  • Heart regularly irregular
  • Irregular heart beat
  • Irregular heart beat
  • Postoperative cardiac arrhythmia
  • Recurrent metabolic encephalomyopathic crises, rhabdomyolysis, cardiac arrhythmia, intellectual disability syndrome
  • Sudden arrhythmic death syndrome
  • Sudden cardiac death
  • Supraventricular arrhythmia
  • Timothy syndrome
  • Ventricular arrhythmia
  • Withdrawal arrhythmia

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.

Cardiac dysrhythmias

CCSR Code: CIR017

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.
  • Arrhythmia (cardiac) 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 I49.9 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.

Cardiac dysrhythmia NOS

ICD-9-CM: 427.9

This is a direct match with no additional mapping qualifiers. The absence of a flag generally means the mapping is considered exact or precise. In other words, the ICD-10 code maps cleanly to the ICD-9 code without qualification, approximation, or needing multiple codes.

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Patient Education


Arrhythmia

An arrhythmia is a problem with the rate or rhythm of your heartbeat. It means that your heart beats too quickly, too slowly, or with an irregular pattern. When the heart beats faster than normal, it is called tachycardia. When the heart beats too slowly, it is called bradycardia. The most common type of arrhythmia is atrial fibrillation, which causes an irregular and fast heart beat.

Many factors can affect your heart's rhythm, such as having had a heart attack, smoking, congenital heart defects, and stress. Some substances or medicines may also cause arrhythmias.

Symptoms of arrhythmias include:

  • Fast or slow heart beat
  • Skipping beats
  • Lightheadedness or dizziness
  • Chest pain
  • Shortness of breath
  • Sweating

Your doctor can run tests to find out if you have an arrhythmia. Treatment to restore a normal heart rhythm may include medicines, an implantable cardioverter-defibrillator (ICD) or pacemaker, or sometimes surgery.

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.