ICD-10 code for AFib (atrial fibrillation)

The ICD-10-CM code for AFib (atrial fibrillation) is I48.91 (Unspecified atrial fibrillation). The official index lists 8 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on I48.91.

It is also searched as a-fib, A fib.

Within I48.9 (unspecified atrial fibrillation and atrial flutter), I48.91 is specifically for unspecified atrial fibrillation. Related codes cover flutter (I48.92).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 308 (Cardiac Arrhythmia and Conduction Disorders with MCC, relative weight 1.1806), DRG 309 (Cardiac Arrhythmia and Conduction Disorders with CC, relative weight 0.7316), DRG 310 (Cardiac Arrhythmia and Conduction Disorders without CC/MCC, relative weight 0.568), DRG 791 (Prematurity with Major Problems, relative weight 4.1075) and DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), in MDC 05 (Diseases and Disorders of the Circulatory System) and MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.