Ejection Fraction in Decompensated Heart Failure
A patient with decompensated heart failure can have any ejection fraction—reduced (≤40%), mildly reduced (41-49%), or preserved (≥50%)—because decompensation refers to the clinical syndrome of worsening symptoms and signs of congestion, not the underlying EF category. 1
Understanding the Distinction
Decompensated heart failure is a clinical state characterized by worsening symptoms (breathlessness, fatigue, ankle swelling) and signs (elevated jugular venous pressure, pulmonary crackles, peripheral edema) resulting from fluid overload and elevated cardiac filling pressures, regardless of the patient's baseline ejection fraction. 1
The ejection fraction classification system exists independently of whether a patient is compensated or decompensated:
EF-Based Classification 1
- HFrEF (Heart Failure with Reduced EF): LVEF ≤40% 1
- HFmrEF (Heart Failure with Mildly Reduced EF): LVEF 41-49% 1
- HFpEF (Heart Failure with Preserved EF): LVEF ≥50% 1
Clinical Implications
Patients in any of these three EF categories can experience acute decompensation requiring hospitalization. 2 The key distinction is that decompensation describes the acute clinical presentation with volume overload and congestion, while EF describes the underlying cardiac systolic function. 1
Decompensation Across EF Categories
- HFrEF patients with LVEF ≤40% can decompensate due to progressive pump failure, medication non-adherence, dietary indiscretion, or acute precipitants. 3
- HFpEF patients with LVEF ≥50% represent approximately 50% of the HF population and are hospitalized approximately 1.4 times per year, with approximately 65% presenting with overt congestion at rest. 1, 2
- HFmrEF patients with LVEF 41-49% represent a transitional zone and can decompensate similarly to either HFrEF or HFpEF patients. 1, 4
Common Pitfalls to Avoid
Do not assume that "decompensated heart failure" automatically means reduced ejection fraction. 1 This is a critical error in clinical reasoning. Approximately half of all heart failure patients have preserved ejection fraction, and they experience decompensation with similar frequency to those with reduced EF. 1, 2
The presence of acute pulmonary edema or severe volume overload does not predict the underlying EF. 1 Both HFrEF and HFpEF patients can present with severe decompensation requiring aggressive diuresis and intensive care. 2
Diagnostic Approach in Acute Decompensation
When evaluating a patient with decompensated HF, measure the LVEF with echocardiography to determine the specific EF category, as this fundamentally guides therapeutic decisions beyond acute diuresis. 1 The EF measurement is essential because:
- HFrEF patients (LVEF ≤40%) benefit from neurohormonal blockade with ACE inhibitors/ARNIs, beta-blockers, mineralocorticoid receptor antagonists, and SGLT2 inhibitors with proven mortality reduction. 3
- HFpEF patients (LVEF ≥50%) benefit primarily from SGLT2 inhibitors for reducing HF hospitalization, with less robust evidence for other therapies. 2
- HFmrEF patients (LVEF 41-49%) may benefit from therapies used in HFrEF, though evidence is less definitive. 4, 5