2026 ICD-10-CM Diagnosis Code I48.20Chronic atrial fibrillation, unspecified
ICD-10-CM Codes›I00–I99›I30-I5A›I48
- Billable — Valid for Submission
- Chronic Condition
I48.20 is a billable ICD-10-CM diagnosis code for chronic atrial fibrillation, unspecified. 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. Coders also document this condition as chronic atrial fibrillation. 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 atrial fibrillation and flutter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Chronic atrial fibrillation
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Type 1 Excludes
- Chronic persistent atrial fibrillation I48.19
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.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- atrial or auricular (established) - I48.91
- chronic - I48.20
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Fibrillation
- atrial or auricular (established)
- chronic
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Atrial Fibrillation
Atrial fibrillation, also known as AFib or AF, is one of the most common types of arrhythmias. Arrhythmias are problems with the rate or rhythm of your heartbeat. They can cause your heart to beat too slowly, too fast, or in an irregular way.
The full article covers:
- What is atrial fibrillation (AFib)?
- What causes atrial fibrillation (AFib)?
- Who is more likely to develop atrial fibrillation (AFib)?
- What are the symptoms of atrial fibrillation (AFib)?
- What other problems can AFib cause?
- How is atrial fibrillation (AFib) diagnosed?
- What are the treatments for atrial fibrillation (AFib)?
- Can atrial fibrillation (AFib) be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Code History & ChangesHistory
Replacement I48.20 replaces the following previously assigned code(s):
- I48.2 - Chronic atrial fibrillation
Questions About I48.20Overview
Is I48.20 (Chronic atrial fibrillation) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report chronic atrial fibrillation, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does I48.20 group to?
When chronic atrial fibrillation, unspecified 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.
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.
