Ejection fraction is an important measurement in the diagnosis and surveillance of HF.
However, it is possible for patients with normal ejection fraction to have HF, and this form of the disease, HF with preserved ejection fraction, or HFpEF, is becoming increasingly prevalent. Also known as diastolic HF, this form of HF is related to aging.
Moreover, women are disproportionately affected by HFpEF, outnumbering men 2:1. In HFpEF, the muscles of the heart contract normally and the heart may seem to pump a normal proportion of the blood that enters it. However, heart muscle thickening may cause the ventricle to hold an abnormally small volume of blood.
Therefore, although the heart’s output may still appear to be in the normal range, its limited capacity is inadequate to meet the body’s requirements.
In HF with reduced ejection fraction (HFrEF), also known as systolic HF, the heart muscle is not able to contract adequately and, therefore, expels less oxygen-rich blood into the body. Patients with this form of the disease will have lower-than-normal left ventricular ejection fraction on an echocardiogram.
An LVEF of 50% to 75% indicates a normal pumping ability, whereas a range of 36% to 49% is considered below normal, and 35% or lower is considered low pumping ability. Fatigue and shortness of breath are common symptoms of both HFpEF and HFrEF.
Patients with HFrEF can take steps to manage their low ejection fraction, notably by limiting salt consumption, managing fluid intake and exercising regularly. Those whose HFrEF becomes severe or unmanageable may benefit from an implantable cardioverter defibrillator, which regulates heart rhythm.
For patients with HFpEF, there is not yet an optimal treatment modality. Recent studies have suggested some utility for aldosterone agonists and metalloproteinase inhibitors. However, additional research is warranted to find future treatments for HFpEF.