2026 ICD-10-CM Diagnosis Code I48Atrial fibrillation and flutter

ICD-10-CM Codes›I00–I99›I30-I5A›I48

ICD-10-CM I48
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I48 is a non-billable ICD-10-CM category code for atrial fibrillation and flutter, so it cannot be submitted on claims. Use a more specific code from this category instead, such as I48.0, I48.11, I48.19, and I48.20.

This medical diagnosis code is frequently used in Cardiology medical specialties to designate conditions such atrial fibrillation and flutter.

Code Identity

ICD-10-CM Code
I48
Billable Status
No — Non-Billable Category
Code Describes
Atrial fibrillation and flutter
Chapter
I30-I5A
Other forms of heart disease

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI30-I5AOther forms of heart disease
CategoryI48Atrial fibrillation and flutter
This CodeI48Atrial fibrillation and flutter

Specific Coding for Atrial fibrillation and flutterOverview

Non-specific codes like I48 require more characters. Use one of these billable codes instead:

  • Use I48.0 for Paroxysmal atrial fibrillation

  • I48.1 for Persistent atrial fibrillation

  • Use I48.11 for Longstanding persistent atrial fibrillation

  • Use I48.19 for Other persistent atrial fibrillation

  • I48.2 for Chronic atrial fibrillation

  • Use I48.20 for Chronic atrial fibrillation, unspecified

  • Use I48.21 for Permanent atrial fibrillation

  • Use I48.3 for Typical atrial flutter

  • Use I48.4 for Atypical atrial flutter

  • I48.9 for Unspecified atrial fibrillation and atrial flutter

  • Use I48.91 for Unspecified atrial fibrillation

  • Use I48.92 for Unspecified atrial flutter

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.

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 I48Overview

Is I48 (Atrial fibrillation and flutter) a billable code?

No. This is a category header that groups the codes for atrial fibrillation and flutter, and headers cannot be submitted on claims. Claims for atrial fibrillation and flutter need a more specific code from this category, such as I48.0, I48.11, and I48.19.