Can heart failure exacerbation occur with a normal Ejection Fraction (EF)?

Heart Failure Exacerbation with Normal Ejection Fraction

Yes, heart failure exacerbation can definitely occur in patients with a normal ejection fraction (EF), a condition known as heart failure with preserved ejection fraction (HFpEF). HFpEF represents approximately 50% of all heart failure cases and carries a mortality rate similar to heart failure with reduced ejection fraction (HFrEF) 1.

Understanding HFpEF and Normal EF Heart Failure

The 2022 AHA/ACC/HFSA guidelines define HFpEF as heart failure with an LVEF ≥50% 1. This classification recognizes that heart failure is a clinical syndrome resulting from any structural or functional impairment of ventricular filling or ejection of blood, which can occur even when the ejection fraction appears normal.

Key characteristics of HFpEF include:

• Symptoms and signs of heart failure
• Normal or near-normal left ventricular ejection fraction (≥50%)
• Evidence of diastolic dysfunction
• Elevated left ventricular filling pressures at rest or with exertion

Pathophysiology of Exacerbations with Normal EF

Heart failure exacerbations in patients with normal EF typically involve:

1. Diastolic dysfunction: Characterized by elevated left ventricular stiffness, prolonged iso-volumetric LV relaxation, slow LV filling, and elevated LV end-diastolic pressure 2

2. Impaired longitudinal function: Patients may have "depressed longitudinal LV function despite normal EF" 1

3. Elevated filling pressures: Evidence of spontaneous or provokable increased LV filling pressures is a key diagnostic feature 1

Diagnostic Considerations

The 2022 AHA/ACC/HFSA guidelines emphasize that diagnosing HFpEF requires:

• Classic clinical signs and symptoms of heart failure
• LVEF ≥50%
• Evidence of increased LV filling pressures (at rest or with provocation) 1

This evidence can be obtained through:

• Elevated natriuretic peptide levels
• Echocardiographic parameters (e.g., E/e' ≥15)
• Invasive hemodynamic measurements 1

Common Causes and Risk Factors

Several conditions can lead to heart failure exacerbations despite normal EF:

• Hypertension (most common cause worldwide) 2
• Advanced age
• Obesity
• Diabetes mellitus
• Atrial fibrillation
• Infiltrative cardiomyopathies (e.g., cardiac amyloidosis) 1

Clinical Presentation of Exacerbations

Patients with HFpEF exacerbations may present with:

• Dyspnea (at rest or with exertion)
• Evidence of right-sided heart failure (hepatomegaly, ascites, lower extremity edema)
• Intolerance to ACE inhibitors or beta blockers
• Signs of volume overload 1, 3

Special Consideration: Cardiac Amyloidosis

The 2019 expert consensus on transthyretin cardiac amyloidosis highlights that patients with this condition can present with:

• Heart failure with preserved EF
• Restrictive LV filling with RV wall thickening
• Depressed longitudinal LV function despite normal EF 1

Management Implications

Understanding that heart failure exacerbations can occur with normal EF is critical because:

1. Treatment approaches differ between HFpEF and HFrEF
2. First-line therapy for HFpEF includes SGLT2 inhibitors (dapagliflozin or empagliflozin) 3
3. Loop diuretics remain important for managing congestion and symptoms
4. Exercise training and weight loss (in obese patients) can significantly improve functional capacity 3

Common Pitfalls to Avoid

1. Misdiagnosis: Assuming normal EF excludes heart failure
2. Undertreatment: Failing to address volume overload in HFpEF patients
3. Missing specific etiologies: Not considering conditions like cardiac amyloidosis in patients with HFpEF 1
4. Inadequate evaluation: Relying solely on resting measurements when exertional symptoms predominate

In summary, heart failure exacerbations can and do occur in patients with normal ejection fraction. Recognizing HFpEF as a distinct clinical entity with its own diagnostic criteria and treatment approach is essential for optimal patient management.