[Heart failure with mid-range ejection fraction. Looking for Middle Earth?]

Area of Science:

• Cardiology
• Heart Failure Research

Background:

• The European Society of Cardiology (ESC) updated heart failure (HF) classification based on left ventricular ejection fraction (LVEF).
• Three categories are defined: HF with preserved EF (HFpEF, LVEF ≥50%), mid-range EF (HFmrEF, LVEF 40-49%), and reduced EF (HFrEF, LVEF <40%).
• The HFmrEF category's distinctness is debated, with uncertainty if it's a separate entity or a transitional phase.

Purpose of the Study:

• To critically evaluate the current evidence regarding the characteristics and prognosis of heart failure with mid-range ejection fraction (HFmrEF).
• To discuss the clinical significance and independent classification of the HFmrEF group within the broader heart failure spectrum.

Main Methods:

• Review and synthesis of existing scientific literature and clinical studies on heart failure classification.
• Analysis of data pertaining to patient demographics, clinical presentation, treatment response, and outcomes in the HFmrEF population.
• Comparison of HFmrEF characteristics and prognosis against HFpEF and HFrEF groups.

Main Results:

• Evidence suggests HFmrEF may represent a distinct clinical entity with unique pathophysiological features.
• Prognostic data indicate outcomes for HFmrEF patients may differ from both HFpEF and HFrEF, though variability exists.
• Further research is needed to fully elucidate the independent nature and optimal management strategies for HFmrEF.

Conclusions:

• The HFmrEF classification presents a challenge in distinguishing it as a truly independent category from HFpEF and HFrEF.
• Current evidence supports HFmrEF as a potentially distinct group requiring further investigation for tailored therapeutic approaches.
• Clarifying the HFmrEF category is crucial for refining heart failure diagnosis, management, and improving patient outcomes.