ICD-10-CM 2027
ICD-10 code for acute systolic heart failure
Acute systolic (congestive) heart failure
Confirmed by the official ICD-10-CM index entry “failure, failed › systolic (congestive) (left ventricular) › acute (congestive)”. Page updated September 29, 2026.
About coding acute systolic heart failure
The ICD-10-CM code for acute systolic heart failure is I50.21 (Acute systolic (congestive) heart failure). The official index lists 3 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on I50.21.
Within I50.2 (systolic (congestive) heart failure), I50.21 is specifically for acute systolic (congestive) heart failure. Related codes cover unspecified systolic (congestive) heart failure (I50.20), chronic systolic (congestive) heart failure (I50.22) and acute on chronic systolic (congestive) heart failure (I50.23).
Code first: heart failure complicating abortion or ectopic or molar pregnancy (O00-O07, O08.8), heart failure due to hypertension (I11.0), heart failure due to hypertension with chronic kidney disease (I13.-), heart failure following surgery (I97.13-) and 2 more.
As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" MS-DRG of its family, unless the principal diagnosis excludes it.
Related Acute systolic heart failure codes
Common questions about acute systolic heart failure ICD-10 codes
What is the ICD-10 code for acute systolic heart failure?
- I50.21 — Acute systolic (congestive) heart failure. More specific codes apply when the documentation supports them: I50.20, I50.22, I50.23.
What is the ICD-10 code for unspecified systolic (congestive) heart failure?
- I50.20 — Unspecified systolic (congestive) heart failure.
What is the ICD-10 code for chronic systolic (congestive) heart failure?
- I50.22 — Chronic systolic (congestive) heart failure.
What is the ICD-10 code for acute on chronic systolic (congestive) heart failure?
- I50.23 — Acute on chronic systolic (congestive) heart failure.
Is I50.21 billable?
- Yes. I50.21 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can I50.21 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict I50.21 as a principal diagnosis.
Is I50.21 a CC or MCC?
- I50.21 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.