How is heart failure categorized and managed based on ejection fraction (EF)?

Heart Failure Classification by Ejection Fraction

Heart failure is classified into three main categories based on left ventricular ejection fraction (LVEF): HFrEF (≤40%), HFmrEF (41-49%), and HFpEF (≥50%), with each category requiring different management approaches.

Classification System

The 2022 AHA/ACC/HFSA guidelines define heart failure categories by ejection fraction as follows 1:

• Heart Failure with Reduced Ejection Fraction (HFrEF): LVEF ≤40%
• Heart Failure with Mildly Reduced Ejection Fraction (HFmrEF): LVEF 41-49%
• Heart Failure with Preserved Ejection Fraction (HFpEF): LVEF ≥50%

Additionally, a fourth category has been recognized 2:

• Heart Failure with Improved Ejection Fraction (HFimpEF): Baseline LVEF ≤40% that improves by ≥10 points to >40%

Diagnostic Approach

For all heart failure categories, diagnosis requires:

• Clinical symptoms and signs of heart failure
• Evidence of structural heart disease or cardiac dysfunction
• For HFpEF and HFmrEF: evidence of elevated LV filling pressures (at rest or with exertion) 3

Key diagnostic tools include:

• Echocardiography to determine LVEF
• Natriuretic peptide levels (elevated in all types)
• Evidence of pulmonary or systemic congestion 3

Management Based on EF Category

HFrEF (LVEF ≤40%)

• First-line therapies (mortality benefit proven):
  • ACE inhibitors/ARBs/ARNI
  • Beta-blockers
  • Mineralocorticoid receptor antagonists (MRAs) 4
  • SGLT2 inhibitors
  • Loop diuretics for symptom management

HFmrEF (LVEF 41-49%)

• Patients with HFmrEF often represent a dynamic state, either improving from HFrEF or deteriorating toward HFrEF 1
• Management approach:
  • Consider similar therapies as HFrEF, particularly if previously had HFrEF 5
  • SGLT2 inhibitors have shown benefit
  • Treat underlying causes (especially ischemic heart disease, which is common in this group) 5
  • Monitor LVEF trajectory over time, as a single measurement may not be adequate 1

HFpEF (LVEF ≥50%)

• Represents approximately 50% of all heart failure cases 3
• Management approach:
  • SGLT2 inhibitors (first-line therapy with proven benefit) 3, 6
  • Loop diuretics for congestion management
  • Non-steroidal MRAs may provide benefit 6
  • Exercise training and weight loss (if obese) to improve functional capacity 3
  • Aggressive management of comorbidities (hypertension, diabetes, atrial fibrillation)

Clinical Considerations

Trajectory and Prognosis

• HFmrEF often represents a transitional state rather than a stable condition 1, 5
• HFpEF carries mortality rates similar to HFrEF despite preserved systolic function 3
• HFimpEF patients require continued therapy despite improvement in EF 2

Common Pitfalls

• Assuming normal EF excludes heart failure
• Failing to address volume overload in HFpEF patients
• Missing specific etiologies like cardiac amyloidosis
• Inadequate evaluation when symptoms are primarily exertional 3
• Relying on a single EF measurement for HFmrEF patients without considering trajectory 1

Special Considerations

• Patients with HFpEF often have impaired longitudinal function despite normal EF 3
• Elevated filling pressures are a key diagnostic feature of HFpEF 3
• HFmrEF has a clinical profile closer to HFpEF but with certain distinctions 7

The classification of heart failure by ejection fraction guides therapeutic decisions and helps predict prognosis, but clinicians should recognize that LVEF is a continuous variable and cutpoints are somewhat arbitrary 8. Treatment should be guided by the specific category of heart failure, underlying etiology, and patient-specific factors.