ICD-10-CM 2026 · Effective October 1, 2025

ICD-10 I49.9

Billable / Specific

Cardiac arrhythmia, unspecified

I49
Block
1
Synonyms
210
LCDs
17
Payer Policies
42
Linked CPTs

About ICD-10-CM I49.9

ICD-10-CM code I49.9 represents Cardiac arrhythmia, unspecified. This is a billable/specific code in the Circulatory System chapter (block I49). The 2026 edition of ICD-10-CM I49.9 became effective on October 1, 2025.

Inclusion Terms / Approximate Synonyms

Clinical terms and conditions classified under I49.9. Per CMS ICD-10-CM Tabular 2026.

  • Arrhythmia (cardiac) NOS

Medicare LCD Coverage for I49.9

Local Coverage Determinations (LCDs) from CMS MACs that list I49.9 as a covered diagnosis.

210 LCDs

Showing top 10 of 210 total . Click a CPT for full coverage scope.

CMS LCD: Billing and Coding: Magnesium
Article ID: 59186, Effective: 2025-10-01 00:00:00, 4358 covered, 0 non-covered
CPT 83735 →
CMS LCD: Billing and Coding: Cardiac Radionuclide Imaging
Article ID: 56476, Effective: 2025-10-01 00:00:00, 627 covered, 0 non-covered
CPT A4641 →
CMS LCD: Billing and Coding: Cardiac Radionuclide Imaging
Article ID: 56476, Effective: 2025-10-01 00:00:00, 627 covered, 0 non-covered
CPT J0461 →
CMS LCD: Billing and Coding: Cardiac Radionuclide Imaging
Article ID: 56476, Effective: 2025-10-01 00:00:00, 627 covered, 0 non-covered
CPT A9611 →
CMS LCD: Billing and Coding: Cardiac Radionuclide Imaging
Article ID: 56476, Effective: 2025-10-01 00:00:00, 627 covered, 0 non-covered
CPT 78454 →
CMS LCD: Billing and Coding: Cardiac Radionuclide Imaging
Article ID: 56476, Effective: 2025-10-01 00:00:00, 627 covered, 0 non-covered
CPT J1245 →
CMS LCD: Billing and Coding: Cardiac Radionuclide Imaging
Article ID: 56476, Effective: 2025-10-01 00:00:00, 627 covered, 0 non-covered
CPT 78453 →
CMS LCD: Billing and Coding: Cardiac Radionuclide Imaging
Article ID: 56476, Effective: 2025-10-01 00:00:00, 627 covered, 0 non-covered
CPT A9500 →
CMS LCD: Billing and Coding: Cardiac Radionuclide Imaging
Article ID: 56476, Effective: 2025-10-01 00:00:00, 627 covered, 0 non-covered
CPT J0280 →
CMS LCD: Billing and Coding: Cardiac Radionuclide Imaging
Article ID: 56476, Effective: 2025-10-01 00:00:00, 627 covered, 0 non-covered
CPT J1250 →

Commercial Payer Coverage

Coverage policies from major commercial payers referencing I49.9.

17 policies

5 Aetna

Oxygen - Medical Clinical Policy Bulletins | Aetna
Policy ID: CPB-0002
Holter Monitors - Medical Clinical Policy Bulletins | Aetna
Policy ID: CPB-0019
Cardiac Event Monitors - Medical Clinical Policy Bulletins | Aetna
Policy ID: CPB-0073
Heart Transplantation
Policy ID: CPB-0586
Brain Natriuretic Peptide Testing
Policy ID: CPB-0618

1 Cigna

Transthoracic Echocardiography in Adults - (0510)
Policy ID: MM_0510

5 Medicare

Billing and Coding: Implantable Automatic Defibrillators
Policy ID: ART-56326
Billing and Coding: Implantable Automatic Defibrillators
Policy ID: ART-56340
Billing and Coding: Implantable Automatic Defibrillators
Policy ID: ART-56343
Billing and Coding: Implantable Automatic Defibrillators
Policy ID: ART-56391
Billing and Coding: Cardiac Radionuclide Imaging
Policy ID: ART-56476

CPT Codes Commonly Billed with I49.9

Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.

42 linkages
  • 93000 EKG 12-lead — tachycardia, bradycardia, palpitations, HTN, CAD, AFib, arrhythmia, chest pain, syncope, cardiomyopathy, AV block, bundle branch block, SVT, VT, diabetes screening, abnormal EKG Cardiology
  • 93010 EKG interpretation only — same dx as 93000 Cardiology
  • G0448 CMS LCD: Billing and Coding: Implantable Automatic Defibrillators CMS LCD
  • 33216 CMS LCD: Billing and Coding: Implantable Automatic Defibrillators CMS LCD
  • 33230 CMS LCD: Billing and Coding: Implantable Automatic Defibrillators CMS LCD
  • 33244 CMS LCD: Billing and Coding: Implantable Automatic Defibrillators CMS LCD
  • 33264 CMS LCD: Billing and Coding: Implantable Automatic Defibrillators CMS LCD
  • 33263 CMS LCD: Billing and Coding: Implantable Automatic Defibrillators CMS LCD
  • 33220 CMS LCD: Billing and Coding: Implantable Automatic Defibrillators CMS LCD
  • 33224 CMS LCD: Billing and Coding: Implantable Automatic Defibrillators CMS LCD

Convert I49.9 to ICD-9-CM

Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.

ICD-10ICD-9Mapping Flags
I49.9 4279 00000

Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).

ICD-10 I49.9, Billing FAQ

Is ICD-10 code I49.9 billable? +

Yes, I49.9 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.

What other names or terms map to I49.9? +

ICD-10 I49.9 includes: Arrhythmia (cardiac) NOS.

What CPT codes are commonly billed with I49.9? +

Procedures frequently paired with I49.9 include: 93000, 93010, G0448, 33216, 33230.

What ICD-9 codes does I49.9 map to? +

Per CMS GEMs, I49.9 maps to ICD-9 codes: 4279. Useful for legacy data review and historical claim analysis.

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Reviewed by the PayerReady Medical Coding Team

Verified against the CMS 2026 code set on June 1, 2026.

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