I48.4 — Atypical atrial flutter
Is I48.4 billable?
Yes — I48.4 is billable for FY2027. I48.4 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. I48.4 may be submitted for encounters from October 1, 2026 through September 30, 2027.
I48.4 at a glance
| Code | I48.4 |
|---|---|
| Description | Atypical atrial flutter |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does I48.4 group to?
I48.4 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
As a secondary diagnosis, I48.4 is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is I48.4 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to I48.4. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Flutter › atrial or auricular › atypical
- Flutter › atrial or auricular › type II
- Flutter › heart › atrial or auricular › atypical
- Flutter › heart › atrial or auricular › type II
Inclusion terms
Alternative wording in documentation that is classified to I48.4.
- Type II atrial flutter
Excludes2 — not included here — inherited from Chapter 9
The conditions below are not part of I48.4, but a patient may have both at the same time. When documentation supports it, I48.4 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.-)
How long has I48.4 existed?
I48.4 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.