Area of Science:

• Cardiology
• Heart Failure Research

Background:

• Heart failure (HF) classification traditionally categorizes patients based on left ventricular ejection fraction (LVEF) into reduced (<40%), mid-range (40-49%), and preserved (≥50%) groups.
• Patients with mid-range LVEF exhibit heterogeneous clinical and demographic characteristics, often occupying an intermediate position between reduced and preserved LVEF groups.

Purpose of the Study:

• To evaluate the clinical expediency of a separate classification subgroup for heart failure patients with mid-range ejection fraction (40-49%).
• To analyze the treatment response and etiological differences within the mid-range LVEF subgroup compared to reduced and preserved LVEF groups.
• To advocate for a revised HF classification incorporating clinical phenotype alongside LVEF.

Main Methods:

• Analysis of studies published between 2017-2018 focusing on patients with mid-range LVEF.
• Comparison of clinical and demographic parameters, treatment responses (beta-blockers, RAAS inhibitors), and etiological factors (ischemic vs. non-ischemic phenotypes) across different LVEF groups.

Main Results:

• Patients with mid-range LVEF demonstrate a positive response to beta-blocker and RAAS inhibitor therapy, similar to patients with reduced LVEF.
• This therapeutic response differs significantly from patients with preserved LVEF, who typically do not benefit from these treatments.
• Etiology plays a key role, with ischemic heart disease prevalent in reduced and mid-range LVEF, while non-cardiac causes are more common in preserved LVEF.

Conclusions:

• The mid-range LVEF subgroup is clinically distinct and warrants separate consideration.
• The positive response to specific therapies in mid-range LVEF suggests a pathogenesis more aligned with reduced LVEF, primarily linked to ischemic heart disease.
• A comprehensive HF classification should integrate clinical phenotype (e.g., ischemic vs. non-ischemic) with LVEF, especially for the heterogeneous mid-range group, to guide therapeutic strategies.