I49 ICD-10-CM Code: Other cardiac arrhythmias
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Diseases of the circulatory system (I00-I99) / Other forms of heart disease (I30-I5A)
I49
Header CodeICD-10-CMOfficial ICD-10-CMCodebook guidanceOther cardiac arrhythmias
Other cardiac 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
OfficialICD-10-CM does not list inclusion terms for I49 in this effective period.
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 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for I49 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 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for I49 in this effective period.
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Coder workflow notes
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What This Code Means
I49 is the ICD-10-CM diagnosis code for other cardiac arrhythmias. I49 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).
Header codes like I49 cannot be reported on claims directly, they organize child codes that share clinical context but the actual diagnosis must be coded to the highest level of specificity supported by the documentation. Coders should look at I49's child codes and select the one that matches the patient's documented presentation, since payers reject header codes submitted as the primary diagnosis. For risk adjustment workflows, header codes never contribute to a Medicare Advantage member's RAF score on their own; only billable child codes that happen to map to a payment HCC affect risk-adjusted plan payments.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for I49 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.