2026 ICD-10-CM Diagnosis Code I97.121Postprocedural cardiac arrest following other surgery

ICD-10-CM Codes›I00–I99›I95-I99›I97

ICD-10-CM I97.121
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I97.121 is a billable ICD-10-CM diagnosis code for postprocedural cardiac arrest following other surgery. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 314 through 316, 791, 793. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 60 closely related codes. Coders also document this condition as cardiac arrest due to procedure. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cardiac arrest and ventricular fibrillation and Postprocedural or postoperative circulatory system complication.

Code Identity

ICD-10-CM Code
I97.121
Billable Status
Yes — Valid for Submission
Code Describes
Postprocedural cardiac arrest following other surgery
Short Description
Postprocedural cardiac arrest following other surgery
Same as the full description in the CMS dataset.
Parent Code
I97.12
Postprocedural cardiac arrest

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI95-I99Other and unspecified disorders of the circulatory system
CategoryI97Intraoperative and postprocedural complications and disorders of circulatory system, not elsewhere classified
This CodeI97.121Postprocedural cardiac arrest following other surgery

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cardiac arrest due to procedure
  • Cardiorespiratory arrest
  • Postoperative cardiac arrhythmia
  • Postoperative cardiopulmonary failure
  • Postprocedural respiratory failure
  • Respiratory arrest

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.

CCSR CIR018
Cardiac arrest and ventricular fibrillation
Default principal diagnosis: inpatient No · outpatient No
CCSR CIR038
Postprocedural or postoperative circulatory system complication
Default principal diagnosis: inpatient Yes · outpatient Yes

Convert I97.121 to ICD-9-CMHistory

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

ICD-9-CM
429.4 Hrt dis postcardiac surg
Approximate The match is approximate rather than exact.
ICD-9-CM
997.1 Surg compl-heart
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
429.4 Hrt dis postcardiac surg
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

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 I97.121Overview

What is the ICD-10 code for postprocedural cardiac arrest following other surgery?

The ICD-10-CM code for postprocedural cardiac arrest following other surgery is I97.121 (sometimes written as I97121). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is I97.121 (Postprocedural cardiac arrest) a billable code?

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

What MS-DRG does I97.121 group to?

When postprocedural cardiac arrest following other surgery is the principal diagnosis on an inpatient stay, it groups to MS-DRG 314, 315, 316, 791, 793, with relative weights from 0.6821 to 4.1696 depending on complications. Higher weights mean higher Medicare reimbursement.

Is I97.121 a CC or MCC?

CMS lists I97.121 as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 60 closely related codes in its exclusion list.

What is the ICD-9 equivalent of I97.121?

Under the General Equivalence Mappings, postprocedural cardiac arrest following other surgery converts to ICD-9-CM 429.4 (hrt dis postcardiac surg), 997.1 (surg compl-heart), and 429.4 (hrt dis postcardiac surg). The mapping is approximate, so confirm the match fits the documentation.