ICD-10-CM 2027
ICD-10 code for cardiac fibrillation
From the official ICD-10-CM alphabetic index entry “Fibrillation › cardiac”. Page updated September 29, 2026.
About coding cardiac fibrillation
The ICD-10-CM code for cardiac fibrillation is I49.89 (Other specified cardiac arrhythmias not elsewhere classified).
Within I49.8 (other specified cardiac arrhythmias), I49.89 is specifically for other specified cardiac arrhythmias not elsewhere classified. Related codes cover Brugada syndrome (I49.81) and ventricular bigeminy (I49.82).
Code first cardiac arrhythmia complicating: abortion or ectopic or molar pregnancy (O00-O07, O08.8) and obstetric surgery and procedures (O75.4).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
Common questions about cardiac fibrillation ICD-10 codes
What is the ICD-10 code for cardiac fibrillation?
- I49.89 — Other specified cardiac arrhythmias not elsewhere classified.
Is I49.89 billable?
- Yes. I49.89 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can I49.89 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict I49.89 as a principal diagnosis.
Is I49.89 a CC or MCC?
- No. I49.89 is neither a CC nor an MCC under MS-DRG v44.0.