ICD-10-CM 2027 diagnosis code

I48Atrial fibrillation and flutter

Not billable — use a more specific code

I48 is a header code, so it can't be reported by itself. Choose one of the 6 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About I48

I48 is the ICD-10-CM diagnosis code for atrial fibrillation and flutter. It belongs to block I30-I5A (other forms of heart disease) and chapter 9 (diseases of the circulatory system). It is a header code, so it can't be reported by itself; one of its 6 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: I48.0 (fibrillation), I48.1 (fibrillation), I48.2 (fibrillation), I48.3 (flutter), I48.4 (flutter) and I48.9 (flutter).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under I48

Notes that apply from higher levels

Instructions written at a parent level also apply to I48.

Broader instructions also apply from Chapter 9: Diseases of the circulatory system.

Code history

2016
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2027

FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
No changes since FY2016.

Common questions about I48

Is I48 billable?: No. I48 is a header code. Report one of its more specific subcodes instead.