2026 ICD-10-CM Diagnosis Code I49.8Other specified cardiac arrhythmias

ICD-10-CM Codes›I00–I99›I30-I5A›I49

ICD-10-CM I49.8
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I49.8 is a billable ICD-10-CM diagnosis code for other specified cardiac arrhythmias. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 308 through 310. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cardiac dysrhythmias.

This medical diagnosis code is frequently used in Cardiology medical specialties to designate conditions such cardiac arrhythmias (other).

Code Identity

ICD-10-CM Code
I49.8
Billable Status
Yes — Valid for Submission
Code Describes
Other specified cardiac arrhythmias
Short Description
Other specified cardiac arrhythmias
Same as the full description in the CMS dataset.
Parent Code
I49
Other cardiac arrhythmias

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI30-I5AOther forms of heart disease
CategoryI49Other cardiac arrhythmias
This CodeI49.8Other specified cardiac arrhythmias

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acquired Brugada syndrome
  • Ankyrin-B syndrome
  • Antidromic atrioventricular re-entrant tachycardia
  • Atrial arrhythmia
  • Atrial escape complex
  • Atrial rhythm
  • AV junctional arrest
  • AV junctional rhythm
  • AV node arrhythmia
  • AV-junctional bradycardia
  • Bradyarrhythmia
  • Brugada syndrome
  • Chronic atrial and intestinal dysrhythmia
  • Chronic intestinal pseudo-obstruction
  • Congenital conductive hearing loss
  • Ectopic rhythm
  • Finding related to awareness of heart beat
  • Fluttering heart
  • Left atrial rhythm
  • Marked sinus arrhythmia
  • Nodal rhythm disorder
  • Orthodromic atrioventricular re-entrant tachycardia
  • Palpitations
  • Phocomelia
  • Phocomelia, ectrodactyly, deafness and sinus arrhythmia syndrome
  • Postoperative fluttering heart
  • Progressive encephalopathy with edema, hypsarrhythmia and optic atrophy syndrome
  • Progressive encephalopathy with edema, hypsarrhythmia, and optic atrophy-like syndrome
  • Re-entrant atrioventricular node tachycardia
  • Re-entrant atrioventricular tachycardia
  • Second cranial nerve finding
  • Short QT syndrome
  • Sick sinus syndrome
  • Slow ventricular response
  • Stable bradyarrhythmia
  • Supraventricular bradyarrhythmia
  • Tic-tac rhythm
  • Ventricular escape complex
  • Wandering atrial pacemaker

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Brugada syndrome
  • Coronary sinus rhythm disorder
  • Ectopic rhythm disorder
  • Nodal rhythm disorder

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Arrhythmia(auricle)(cardiac)(juvenile)(nodal)(reflex)(supraventricular)(transitory)(ventricle)
      • sinus
    • Arrhythmia(auricle)(cardiac)(juvenile)(nodal)(reflex)(supraventricular)(transitory)(ventricle)
      • specified NEC
    • Bradyarrhythmia, cardiac
    • Fibrillation
      • cardiac
    • Fibrillation
      • heart
    • Flutter
      • heart
    • Incompetency, incompetent, incompetence
      • chronotropic
        • with
          • sinus node dysfunction
    • Nodal rhythm
    • Rhythm
      • atrioventricular nodal
    • Rhythm
      • disorder
        • coronary sinus
    • Rhythm
      • disorder
        • ectopic
    • Rhythm
      • disorder
        • nodal
    • Rhythm
      • nodal
    • Sinus
      • arrhythmia
    • Syndrome
      • Brugada
    • Wandering
      • pacemaker (heart)

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR CIR017
Cardiac dysrhythmias
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Sick Sinus Syndrome

    a condition caused by dysfunctions related to the sinoatrial node including impulse generation (cardiac sinus arrest) and impulse conduction (sinoatrial exit block). it is characterized by persistent bradycardia, chronic atrial fibrillation, and failure to resume sinus rhythm following cardioversion. this syndrome can be congenital or acquired, particularly after surgical correction for heart defects.

  • Brugada Syndrome

    an autosomal dominant defect of cardiac conduction that is characterized by an abnormal st-segment in leads v1-v3 on the electrocardiogram resembling a right bundle-branch block; high risk of ventricular tachycardia; or ventricular fibrillation; syncopal episode; and possible sudden death. this syndrome is linked to mutations of gene encoding the cardiac sodium channel alpha subunit.

Patient EducationClinical

Arrhythmia

An arrhythmia is a problem with the rate or rhythm of your heartbeat. Your heart beats too quickly, too slowly, or with an irregular pattern. Changes in the electrical signals that control your heartbeat cause arrhythmias.

The full article covers:

  • What is an arrhythmia?
  • What causes an arrhythmia?
  • What are the symptoms of an arrhythmia?
  • How is an arrhythmia diagnosed?
  • What are the treatments for an arrhythmia?
  • Can arrhythmias be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert I49.8 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
427.89 Cardiac dysrhythmias NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About I49.8Overview

Is I49.8 (Other cardiac arrhythmias) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other specified cardiac arrhythmias on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does I49.8 group to?

When other specified cardiac arrhythmias is the principal diagnosis on an inpatient stay, it groups to MS-DRG 308, 309, 310, with relative weights from 0.5661 to 1.2040 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of I49.8?

Under the General Equivalence Mappings, other specified cardiac arrhythmias converts to ICD-9-CM 427.89 (cardiac dysrhythmias NEC). The mapping is approximate, so confirm the match fits the documentation.

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.