ICD-10 Code I50.43 – Acute on chronic combined systolic (congestive) and diastolic (congestive) heart failure (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I50.43 – Acute on chronic combined systolic (congestive) and diastolic (congestive) heart failure
What it is
This code identifies heart failure with both systolic and diastolic dysfunction when an acute episode occurs on top of a chronic condition. Use it when the record clearly states acute on chronic combined congestive heart failure.
Clinical signs
Clinical features vary; refer to documentation. Common findings in heart failure may include dyspnea, edema, fatigue, and signs of fluid overload, but the code depends on the documented combined systolic and diastolic nature.
When to use this code
Use I50.43 when the provider documents an acute decompensation superimposed on chronic combined systolic and diastolic heart failure. It is appropriate when both components are explicitly stated in the assessment, discharge summary, or problem list.
If the note only says “CHF,” “heart failure,” or names one type without the combined acute-on-chronic wording, check documentation before assigning this code. The specificity must support both chronicity and the mixed systolic/diastolic diagnosis.
Do not use for
Do not use this code for isolated systolic heart failure, isolated diastolic heart failure, or unspecified heart failure. Also avoid it when the chart does not clearly document the acute-on-chronic combined condition.
Coding tip
Look for exact provider wording that links acute, chronic, systolic, and diastolic heart failure; if any part is missing, query or check documentation.