Our heart is made of 4 chambers:
- The right and left atria or the upper, smaller chambers of the heart and
- The right and left ventricles or the lower chambers of the heart.
Of these, the left ventricle is an important chamber in the context of heart failure as this is the chamber that pumps blood out to the rest of the body.
Left ventricular Ejection fraction (LVEF); commonly known as ejection fraction, is a measure of left ventricular function. In simple terms , it is the % of blood that gets pumped out when the left ventricle contracts out of the total blood available in the left ventricle when it is relaxing between heart beats.
Ejection fraction therefore lets us know the ability of the heart to pump blood to meet the requirements of the body. A low ejection fraction means your heart is unable to pump enough blood and you may be at risk of developing heart failure.
The simplest classification as per the American College of Cardiology (ACC) that is used clinically is as follows:
- Normal = LVEF 50% to 70% (midpoint 60%)
- Mildly abnormal = LVEF 40% to 49% (midpoint 45%)
- Moderately abnormal = LVEF 30% to 39% (midpoint 35%)
- Severely abnormal = LVEF less than 30%
People with a normal ejection fraction may also have heart failure. This is known as heart failure with preserved ejection fraction (HFpEF).
Ejection fraction plays an important role in assessing the severity heart failure and to understand the impact of therapy on the patient.
Ejection fraction is recommended as a measure when :
- Assessing the function of the left ventricle – quality- and quantity-wise
- Monitoring patients with signs and symptoms at risk of / or having cardiovascular diseases
- Diagnosing the type of heart failure : with preserved (HFpEF) or reduced ejection fraction (HFrEF)
- Diagnosing abnormal heart beats or structural abnormalities of the heart
- Assessing birth defects of the heart
Ejection fraction is commonly measured by any of the following techniques among others:
- Echocardiography
- Magnetic resonance imaging (MRI)
- Computed tomography (CT)
Clinical Significance
Left ventricular ejection fraction is a powerful predictor of cardiac deaths with a decreased rate of deaths with progressively increasing ejection fractions in heart failure patients. Improving ejection fraction is best achieved by multidisciplinary team including doctors, nurses, dieticians, and pharmacists.
Reference :
Kosaraju A, Goyal A, Grigorova Y, et al. Left Ventricular Ejection Fraction. [Updated 2022 May 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459131/ accessed on 19th Feb 2023
