I46.8 Cardiac arrest due to other underlying condition

Billable ICD-10-CM code, FY2026. Acts as a Major Complication or Comorbidity (MCC) as a secondary diagnosis.

Code first

• underlying condition

Applies from I46 Cardiac arrest

Excludes2 (not included here)

• cardiogenic shock (R57.0)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 213 — Cardio-Respiratory Failure and Shock
• CMS-HCC V22: HCC 84 — Cardio-Respiratory Failure and Shock
• ESRD V24: HCC 84

MS-DRG index

Defines the logic of DRG(s) 296-298 in MDC 05.

Approximate ICD-9-CM (GEMs)

• 427.5 Cardiac arrest (approximate)

Medicare Code Edits (MCE v43.1 (April 2026))

• Unacceptable principal diagnosis: These codes describe a circumstance which influences care but is not a current illness or injury, or capture only an underlying condition, and are unacceptable as principal diagnosis.

Code annotations containing back-references to I46.8

Back-references to I46

• Type 2 Excludes: I50 Heart failure ("cardiac arrest (I46.-)")
• Type 1 Excludes: R09.2 Respiratory arrest ("cardiac arrest (I46.-)")

Diagnosis Index entries for I46.8

• Arrest, arrested › cardiac › due to › specified condition NEC

Nearby codes

• I46 Cardiac arrest
• I46.2 Cardiac arrest due to underlying cardiac condition
• I46.8 Cardiac arrest due to other underlying condition (this code)
• I46.9 Cardiac arrest, cause unspecified