ICDcodes.org
FY2027

I49.9 — Cardiac arrhythmia, unspecified

BillableUnspecified

Is I49.9 billable?

Yes, but I49.9 is an unspecified code. I49.9 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, I49.9 is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting I49.9 — the more specific alternatives are listed below.

I49.9 at a glance

CodeI49.9
DescriptionCardiac arrhythmia, unspecified
BillableYes
Code setICD-10-CM FY2027
Valid for encountersOctober 1, 2026 – September 30, 2027

Which MS-DRGs does I49.9 group to?

I49.9 sits in MDC 05 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.

  • 308Cardiac Arrhythmia and Conduction Disorders with MCCmedical
  • 309Cardiac Arrhythmia and Conduction Disorders with CCmedical
  • 310Cardiac Arrhythmia and Conduction Disorders without CC/MCCmedical

How is I49.9 listed in the Alphabetic Index?

These are the routes through the Alphabetic Index that lead to I49.9. They show the wording a clinician may have documented, which often differs from the Tabular description.

  • Arrhythmia (auricle)(cardiac)(juvenile)(nodal)(reflex)(supraventricular)(transitory)(ventricle)
  • Action, heart › disorder
  • Action, heart › irregular
  • Disorder › heart action (of)
  • Disturbance › rhythm, heart (s)
  • Dysrhythmia › cardiac
  • Irregular, irregularity › action, heart
  • Rhythm › disorder
  • Rhythm › escape
  • Rhythm › heart, abnormal

Inclusion terms

Alternative wording in documentation that is classified to I49.9.

  • Arrhythmia (cardiac) NOS

Code first — inherited from I49

The underlying condition below must be sequenced before I49.9. I49.9 describes a manifestation and cannot be the principal or first-listed diagnosis.

  • cardiac arrhythmia complicating:
  • abortion or ectopic or molar pregnancy (O00-O07, O08.8)
  • obstetric surgery and procedures (O75.4)

Excludes2 — not included here — inherited from Chapter 9

The conditions below are not part of I49.9, but a patient may have both at the same time. When documentation supports it, I49.9 and the excluded code may both be reported.

  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
  • systemic connective tissue disorders (M30-M36)
  • transient cerebral ischemic attacks and related syndromes (G45.-)

Excludes2 — not included here — inherited from I49

The conditions below are not part of I49.9, but a patient may have both at the same time. When documentation supports it, I49.9 and the excluded code may both be reported.

  • bradycardia NOS (R00.1)
  • neonatal dysrhythmia (P29.1-)
  • sinoatrial bradycardia (R00.1)
  • sinus bradycardia (R00.1)
  • vagal bradycardia (R00.1)

How long has I49.9 existed?

I49.9 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.

Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.

Which conditions are coded to I49.9?

What other codes are in the I49 family? (7)