HFmrEF ICD-10 Code: I50.40

There is no specific ICD-10 code for HFmrEF (heart failure with mildly reduced ejection fraction). The most appropriate code is I50.40 (Unspecified combined systolic and diastolic heart failure) or I50.89 (Other heart failure) depending on how it's documented.

Understanding HFmrEF

HFmrEF is defined as heart failure with ejection fraction between 41-49%. It sits between:

• HFrEF (reduced EF): EF ≤ 40% → Systolic heart failure (I50.2x)
• HFpEF (preserved EF): EF ≥ 50% → Diastolic heart failure (I50.3x)
• HFmrEF (mildly reduced EF): EF 41-49% → No specific code

Coding Options for HFmrEF

Since ICD-10-CM doesn't have a dedicated HFmrEF code, consider these options:

Coding Clinic guidance: When documentation specifies "HFmrEF" or "heart failure with mildly reduced ejection fraction," many facilities use I50.89 (Other heart failure) as it's the most accurate representation of a heart failure type that doesn't fit the standard systolic/diastolic classification.

Code Selection by Acuity

If acuity is documented:

Common Coding Scenarios

Scenario 1: HFmrEF, Chronic, Stable

Documentation: "Chronic HFmrEF, EF 45%, stable on guideline-directed therapy."

Code: I50.42 (Chronic combined systolic and diastolic heart failure) or I50.89 (Other heart failure)

Rationale: Either code is defensible. I50.42 captures the chronic nature and mixed pathophysiology. I50.89 may better reflect the specific HFmrEF terminology.

Scenario 2: Acute Decompensated HFmrEF

Documentation: "Acute decompensated heart failure, known HFmrEF, EF 43%."

Code: I50.41 (Acute combined systolic and diastolic heart failure)

Rationale: The acute decompensation takes precedence. Use the acute combined code since HFmrEF has features of both systolic and diastolic dysfunction.

Scenario 3: New Diagnosis of HFmrEF

Documentation: "New diagnosis heart failure with mildly reduced ejection fraction (EF 47%). Starting lisinopril."

Code: I50.40 or I50.89

Rationale: Without acuity specified, use unspecified combined HF or other HF.

Why No Specific Code?

ICD-10-CM's heart failure classification is based on the older systolic/diastolic terminology:

• Systolic HF = HFrEF (reduced EF)
• Diastolic HF = HFpEF (preserved EF)

HFmrEF is a newer clinical category from the 2016 ESC heart failure guidelines. ICD-10-CM updates haven't yet created a specific code for this classification. Until they do, coders must use the best-fit existing codes.

Documentation Recommendations

When coding HFmrEF, look for:

• Specific EF percentage (to confirm 41-49% range)
• Acuity: acute, chronic, or acute on chronic
• Any underlying cause (ischemic, hypertensive, etc.)
• Whether the provider documents "combined" dysfunction

If documentation just says "heart failure" without EF or type, query for specificity.