What is the ICD-10-CM code for atrial fibrillation (AFib)?

The primary ICD-10-CM code for atrial fibrillation (AFib) is I48.91 (Unspecified atrial fibrillation). There are 6 billable atrial fibrillation (AFib) codes in FY2026, covering different types and underlying causes.

How many ICD-10-CM codes are there for atrial fibrillation (AFib)?

There are 10 ICD-10-CM codes for atrial fibrillation (AFib) in the FY2026 tabular list, of which 6 are billable. These codes fall under Chapter 9 of the ICD-10-CM classification.

Which chapter covers atrial fibrillation (AFib) in ICD-10-CM?

Atrial Fibrillation codes are classified in Chapter 9 of the ICD-10-CM tabular list: I00–I99 — Diseases of the Circulatory System.

ICD-10-CM · Chapter 9 · I00–I99

Atrial Fibrillation ICD-10-CM Codes

ICD-10-CM codes for atrial fibrillation, including paroxysmal, persistent, longstanding persistent, chronic, and permanent AFib.

10Total codes

6Billable

2026FY

Coding Guidance for Atrial Fibrillation

Category I48 separates paroxysmal atrial fibrillation (I48.0), persistent (I48.11), longstanding persistent (I48.19), chronic and permanent (I48.21), and unspecified (I48.91).

Paroxysmal AFib terminates on its own or with intervention within 7 days; persistent lasts beyond 7 days; permanent is AFib the provider and patient have decided not to correct. Code the most specific documented form.

A history of resolved AFib with no current treatment is reported with Z86.79 (personal history of other diseases of the circulatory system), not with an I48 code.

10 codes — FY2026 ICD-10-CMEffective April 1, 2026

I48Atrial fibrillation and flutterNon-Billable I48.0Paroxysmal atrial fibrillationBillable I48.1Persistent atrial fibrillationNon-Billable I48.11Longstanding persistent atrial fibrillationBillable I48.19Other persistent atrial fibrillationBillable I48.2Chronic atrial fibrillationNon-Billable I48.20Chronic atrial fibrillation, unspecifiedBillable I48.21Permanent atrial fibrillationBillable I48.9Unspecified atrial fibrillation and atrial flutterNon-Billable I48.91Unspecified atrial fibrillationBillable

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About these codes

These ICD-10-CM codes are sourced from the official FY2026 tabular list published by the Centers for Medicare & Medicaid Services (CMS), effective April 1, 2026. Click any code for full clinical details including instructional notes, excludes guidance, and DRG mappings.

Browse all of Chapter 9: Diseases of the Circulatory System →