Does a moderately reduced left ventricular ejection fraction of 35–40% on echocardiogram meet the definition of chronic systolic heart failure?

Yes, an LVEF of 35-40% definitively meets the criteria for chronic systolic heart failure with reduced ejection fraction (HFrEF).

Classification Based on LVEF

An echocardiogram showing LVEF of 35-40% classifies this patient as having heart failure with reduced ejection fraction (HFrEF), which is defined as LVEF <40%. 1 This is the standard classification used across major international guidelines and represents systolic dysfunction requiring specific guideline-directed medical therapy.

The most recent 2022 AHA/ACC/HFSA guidelines clearly define HFrEF as LVEF ≤40%, while LVEF 41-49% is classified as heart failure with mildly reduced ejection fraction (HFmrEF), and LVEF ≥50% as heart failure with preserved ejection fraction (HFpEF). 1 Your patient with LVEF 35-40% falls squarely within the HFrEF category.

Terminology: "Chronic" vs "Acute"

The term "chronic" refers to the time course rather than severity. 1 If this patient has had symptoms or known left ventricular dysfunction for weeks to months (rather than acute decompensation or new-onset presentation), this would be considered chronic systolic heart failure. 1 The distinction matters because:

• Chronic HFrEF requires optimization of guideline-directed medical therapy with neurohormonal antagonists 1
• Acute decompensated HF requires immediate hemodynamic stabilization before long-term therapy optimization 1

Clinical Implications of This LVEF Range

This degree of systolic dysfunction (LVEF 35-40%) carries significant prognostic implications and mandates aggressive medical therapy. 2, 3 Research demonstrates that LVEF is an independent predictor of both all-cause and cardiovascular mortality in chronic systolic heart failure, with the 35% threshold showing particularly strong prognostic value. 2

Guideline-Directed Medical Therapy Requirements

For any patient with HFrEF (LVEF ≤40%), the following therapies are Class I recommendations unless contraindicated:

• ACE inhibitors or ARBs (or preferably ARNI if symptomatic) 1
• Beta-blockers (bisoprolol, metoprolol succinate, carvedilol, or nebivolol) 1
• Mineralocorticoid receptor antagonists for NYHA class II-IV symptoms 1
• SGLT2 inhibitors (dapagliflozin or empagliflozin) 1, 3

Device Therapy Considerations

With LVEF 35-40%, this patient may qualify for device therapies depending on additional factors:

• Cardiac resynchronization therapy (CRT) if LVEF ≤35%, NYHA class II-IV symptoms, sinus rhythm, and QRS ≥150 ms (or 120-149 ms with mechanical dyssynchrony) 1
• Implantable cardioverter-defibrillator (ICD) if LVEF ≤35% for primary prevention of sudden cardiac death 1

Note that the upper end of your patient's range (LVEF 40%) would not qualify for these devices, but LVEF 35% would meet criteria. 1

Prognostic Significance

Patients with LVEF ≤35% have significantly worse prognosis compared to those with LVEF >35%, with higher rates of all-cause death, cardiovascular death, and heart failure hospitalization. 2 However, even patients with "mild" systolic dysfunction (LVEF >35% but <50%) have substantial mortality risk and benefit from neurohormonal antagonist therapy. 4

The 5-year survival rate after hospitalization for HFrEF is only 25%, underscoring the critical importance of early diagnosis and aggressive treatment. 3

Common Pitfalls to Avoid

• Do not delay treatment waiting for symptoms to worsen—asymptomatic left ventricular systolic dysfunction (Stage B heart failure) already warrants ACE inhibitor and beta-blocker therapy 1
• Do not use the term "diastolic heart failure" for patients with reduced LVEF—most patients with systolic dysfunction also have diastolic dysfunction, making this terminology confusing 1
• Do not assume LVEF improvement means cure—patients with improved LVEF (HFimpEF) should continue HFrEF therapies as discontinuation often leads to recurrent dysfunction 1