Atrial fibrillation is classified under ICD-10-CM code I48, which requires specifying the type. Common billable codes include I48.0 (paroxysmal), I48.11 (longstanding persistent), I48.19 (other persistent), and I48.21 (permanent).
Primary codes
Billable
Billable
Extension
—
7th character
—
POA exempt
No
Coding risks
- Coding a suspected or rule-out condition as confirmed
Hierarchy
Code comparison
Compare key differences between related codes to select the most specific option.
| Code | Description | Scenario |
|---|---|---|
| I48.0 | Paroxysmal atrial fibrillation | AFib episodes that self-terminate within seven days, no sustained or permanent pattern documented. |
| I48.11 | Longstanding persistent atrial fibrillation | AFib documented as continuous for more than 12 months, with rhythm control still being pursued. |
| I48.19 | Other persistent atrial fibrillation | AFib persistent beyond seven days but not documented as longstanding or permanent, requiring cardioversion. |
| I48.21 | Permanent atrial fibrillation | AFib documented as permanent, with no further attempts planned to restore or maintain sinus rhythm. |
Select the most specific code supported by the encounter documentation. More specific codes improve reimbursement accuracy and reduce audit risk.
Code ranges
Atrial fibrillation and flutter
Supraventricular tachyarrhythmias characterized by disorganized atrial electrical activity, subdivided by chronicity (paroxysmal, persistent, chronic, permanent) and flutter type.
Other forms of heart disease
Non-ischemic cardiac conditions including pericarditis, endocarditis, cardiomyopathy, conduction disorders, arrhythmias, and heart failure.
Paroxysmal tachycardia
Episodes of rapid heart rate originating from re-entry or ectopic foci, including supraventricular, ventricular, and junctional tachycardias.
Other cardiac arrhythmias
Includes ventricular fibrillation and flutter, premature beats, sick sinus syndrome, and other unspecified rhythm disturbances.
Other conduction disorders
Bundle branch blocks, fascicular blocks, pre-excitation syndromes, and other atrioventricular or intraventricular conduction abnormalities.
Coding risks
Avoid these common coding issues when reporting Atrial Fibrillation.
Impact
Assigning a specific I48 subtype without explicit type documentation may miscode paroxysmal AFib as persistent (I48.19) or permanent (I48.21).
Mitigation
Consider querying the provider when type is absent rather than inferring from rhythm strips, medication history, or prior cardioversion attempts.
Related codes
Ancillary and co-coding
Codes commonly reported with the primary diagnosis on the same claim.
Z-code variants
Family history, personal history, or screening encounter codes related to this condition.
In pregnancy
Pregnancy-specific O-code adaptations used in place of the primary when the condition occurs during or complicates pregnancy.
Differential codes
Alternative or commonly confused codes to consider when documentation suggests a different condition than the primary diagnosis.
Frequently asked questions
When long-term anticoagulant use is documented, add Z79.01 alongside the I48 code to capture the chronic medication status.
References
Compiled from the following authoritative coding references. Last updated 2026-08-04.