2026 ICD-10-CM Diagnosis Code I46.2Cardiac arrest due to underlying cardiac condition
ICD-10-CM Codes›I00–I99›I30-I5A›I46
- Billable — Valid for Submission
- MCC — Major Complication or Comorbidity
- Risk Adjusts — HCC 213
- Not a Principal Diagnosis
- Chronic Condition
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, 791, 793. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. This status applies only when the patient is discharged alive, and not when the principal diagnosis is one of 24 closely related codes. 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.
For Medicare Advantage risk adjustment, I46.2 maps to CMS-HCC Category 213 (Cardio-Respiratory Failure and Shock) under the V28 model, adding a risk factor of about 0.370 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for I46.2.
Medicare Risk Adjustment (HCC)Billing
I46.2 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2026.
Source: CMS Payment Year 2026 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
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
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
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.
Code HistoryHistory
Questions About I46.2Overview
What is the ICD-10 code for cardiac arrest due to underlying cardiac condition?
The ICD-10-CM code for cardiac arrest due to underlying cardiac condition is I46.2 (sometimes written as I462). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
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, 791, 793, with relative weights from 0.4551 to 4.1696 depending on complications. Higher weights mean higher Medicare reimbursement.
Is I46.2 a CC or MCC?
CMS lists I46.2 as an MCC (major complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It carries this status only when the patient is discharged alive. It does not count when the principal diagnosis is one of the 24 closely related codes in its exclusion list.
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 HCC is I46.2?
I46.2 (cardiac arrest due to underlying cardiac condition) maps to CMS-HCC Category 213 (Cardio-Respiratory Failure and Shock), commonly written as HCC 213, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 84 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. It does not map to any RxHCC in the Part D prescription drug model.
Does I46.2 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, I46.2 adds a risk adjustment factor of about 0.370 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.258 to 0.662 depending on the payment segment). A more severe related category (HCC 211 and HCC 212) supersedes it when both are reported. See the full factor table on the HCC 213 category page.
