ICD-10-CM 2027
ICD-10 code for arrhythmia
From the official ICD-10-CM alphabetic index entry “Arrhythmia (auricle)(cardiac)(juvenile)(nodal)(reflex)(supraventricular)(transitory)(ventricle)”. Page updated September 29, 2026.
About coding arrhythmia
The ICD-10-CM code for arrhythmia is I49.9 (Cardiac arrhythmia, unspecified). The official index lists 12 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on I49.9.
Within I49, choose I49.9 (Cardiac arrhythmia, unspecified) only when documentation doesn't support a more specific option: ventricular fibrillation and flutter (I49.0), atrial premature depolarization (I49.1), junctional premature depolarization (I49.2), ventricular premature depolarization (I49.3), other and unspecified premature depolarization (I49.4), sick sinus syndrome (I49.5) and other specified cardiac arrhythmias (I49.8).
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.
More specific arrhythmia codes (official index)
- block I45.9 — Conduction disorder, unspecified
- extrasystolic I49.49 — Other premature depolarization
- newborn
- bradycardia P29.12 — Neonatal bradycardia
- occurring before birth P03.819 — Newborn affected by abnormality in fetal (intrauterine) heart rate or rhythm, unspecified as to time of onset
- before onset of labor P03.810 — Newborn affected by abnormality in fetal (intrauterine) heart rate or rhythm before the onset of labor
- during labor P03.811 — Newborn affected by abnormality in fetal (intrauterine) heart rate or rhythm during labor
- tachycardia P29.11 — Neonatal tachycardia
- psychogenic F45.8 — Other somatoform disorders
- sinus I49.89 — Other specified cardiac arrhythmias not elsewhere classified
- specified NEC I49.89 — Other specified cardiac arrhythmias not elsewhere classified
- vagal R55 — Syncope and collapse
- ventricular re-entry I47.0 — Re-entry ventricular arrhythmia
Common questions about arrhythmia ICD-10 codes
What is the ICD-10 code for arrhythmia?
- I49.9 — Cardiac arrhythmia, unspecified. More specific codes apply when the documentation supports them: I45.9, I49.49, P29.12, P03.819 and others below.
What is the ICD-10 code for block arrhythmia?
- I45.9 — Conduction disorder, unspecified.
What is the ICD-10 code for extrasystolic arrhythmia?
- I49.49 — Other premature depolarization.
What is the ICD-10 code for psychogenic arrhythmia?
- F45.8 — Other somatoform disorders.
What is the ICD-10 code for sinus arrhythmia?
- I49.89 — Other specified cardiac arrhythmias not elsewhere classified.
What is the ICD-10 code for vagal arrhythmia?
- R55 — Syncope and collapse.
What is the ICD-10 code for ventricular re-entry arrhythmia?
- I47.0 — Re-entry ventricular arrhythmia.
Is I49.9 billable?
- Yes. I49.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can I49.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict I49.9 as a principal diagnosis.
Is I49.9 a CC or MCC?
- No. I49.9 is neither a CC nor an MCC under MS-DRG v44.0.