I49.8 ICD-10-CM Code: Other specified cardiac arrhythmias
I49.8 is not a CMS-HCC payment code. MEAT criteria · RAF calculator · free HCC coding tools
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FY 2026 Apr update / Diseases of the circulatory system (I00-I99) / Other forms of heart disease (I30-I5A)
I49.8
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceOther specified cardiac arrhythmias
Various heart rhythm abnormalities that don't fit into the more common categories, such as unusual electrical patterns or rare arrhythmias.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
Official- Brugada syndrome
- Coronary sinus rhythm disorder
- Ectopic rhythm disorder
- Nodal rhythm disorder
Excludes 2
Official- bradycardia NOS (R00.1)
- neonatal dysrhythmia (P29.1-)
- sinoatrial bradycardia (R00.1)
- sinus bradycardia (R00.1)
- vagal bradycardia (R00.1)
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for I49.8 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for I49.8 in this effective period.
Code First
Official- cardiac arrhythmia complicating:
- abortion or ectopic or molar pregnancy (O00-O07, O08.8)
- obstetric surgery and procedures (O75.4)
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for I49.8 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for I49.8 in this effective period.
Buddy Documentation Tip
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is I49.8 an HCC code?
No. I49.8 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
- Code
- I49.8
- Description
- Other specified cardiac arrhythmias
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF
- —
- Billable
- Yes
- Payment year
- 2026
Coder workflow notes
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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
I49.8 is the ICD-10-CM diagnosis code for other specified cardiac arrhythmias. Various heart rhythm abnormalities that don't fit into the more common categories, such as unusual electrical patterns or rare arrhythmias. I49.8 sits in the ICD-10-CM chapter for diseases of the circulatory system (i00-i99), within the section covering other forms of heart disease (i30-i5a).
I49.8 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
This is a catch-all code; use only when the specific arrhythmia type is documented but doesn't match codes I49.0-I49.5 or I49.9.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for I49.8 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.