2026 ICD-10-CM Diagnosis Code I46.2Cardiac arrest due to underlying cardiac condition

ICD-10-CM Codes›I00–I99›I30-I5A›I46

ICD-10-CM I46.2
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I46.2 is a billable ICD-10-CM diagnosis code for cardiac arrest due to underlying cardiac condition. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 296 through 298. The code is not accepted as a principal diagnosis by the Medicare Code Editor. Coders also document this condition as bradycardic cardiac arrest. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cardiac arrest and ventricular fibrillation.

Code Identity

ICD-10-CM Code
I46.2
Billable Status
Yes — Valid for Submission
Code Describes
Cardiac arrest due to underlying cardiac condition
Short Description
Cardiac arrest due to underlying cardiac condition
Same as the full description in the CMS dataset.
Parent Code
I46
Cardiac arrest

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI30-I5AOther forms of heart disease
CategoryI46Cardiac arrest
This CodeI46.2Cardiac arrest due to underlying cardiac condition

Code EditsBilling

Medicare Code Editor checks that affect claim validity for I46.2.

Unacceptable principal diagnosis
There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bradycardic cardiac arrest
  • Cardiac arrest due to cardiac disorder

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Code First

  • underlying cardiac condition

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Arrest, arrested
      • cardiac
        • due to
          • cardiac condition

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR CIR018
Cardiac arrest and ventricular fibrillation
Default principal diagnosis: inpatient No · outpatient Yes

Patient EducationClinical

Sudden Cardiac Arrest

Sudden cardiac arrest (SCA) is a condition in which the heart suddenly stops beating. When that happens, blood stops flowing to the brain and other vital organs. If it is not treated, SCA usually causes death within minutes. But quick treatment with a defibrillator may be lifesaving.

The full article covers:

  • What is sudden cardiac arrest (SCA)?
  • How is sudden cardiac arrest (SCA) different from a heart attack?
  • What causes sudden cardiac arrest (SCA)?
  • Who is at risk for sudden cardiac arrest (SCA)?
  • What are the symptoms of sudden cardiac arrest (SCA)?
  • How is sudden cardiac arrest (SCA) diagnosed?
  • What are the treatments for sudden cardiac arrest (SCA)?
  • What should I do if I think that someone has had an SCA?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert I46.2 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
427.5 Cardiac arrest
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About I46.2Overview

Is I46.2 (Cardiac arrest) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report cardiac arrest due to underlying cardiac condition on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does I46.2 group to?

On inpatient claims, cardiac arrest due to underlying cardiac condition maps to MS-DRG 296, 297, 298, with relative weights from 0.4551 to 1.5619 depending on complications. Higher weights mean higher Medicare reimbursement.

Can I46.2 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because cardiac arrest due to underlying cardiac condition describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

What is the ICD-9 equivalent of I46.2?

Under the General Equivalence Mappings, cardiac arrest due to underlying cardiac condition converts to ICD-9-CM 427.5 (cardiac arrest). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.