ICD-10 Code I50.33 – Acute on chronic diastolic (congestive) heart failure (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I50.33 – Acute on chronic diastolic (congestive) heart failure
What it is
This code identifies a sudden worsening of chronic diastolic heart failure, also called heart failure with preserved ejection fraction. It means the heart has difficulty filling properly, leading to congestion and reduced cardiac output.
Clinical signs
Common findings include shortness of breath, fluid retention, edema, orthopnea, and signs of pulmonary or systemic congestion. Clinical features vary; refer to documentation.
When to use this code
Use I50.33 when the record clearly states acute on chronic diastolic heart failure or an equivalent documented diagnosis. It is appropriate when the provider describes both the chronic baseline condition and the acute decompensation. Check documentation if the note only says heart failure, CHF, or fluid overload without specificity.
Do not use for
Do not use this code for isolated acute heart failure, chronic diastolic heart failure without an acute episode, or heart failure type not specified. Do not assign it when the chart supports only edema or dyspnea without a documented heart failure diagnosis.
Coding tip
Code the documented acuity and type together; if either is unclear, query the provider before selecting I50.33.