Ejection fraction indicates heart health by reflecting how effectively the heart pumps blood. This measurement helps healthcare providers assess the heart’s overall function and pumping efficiency.
What is Ejection Fraction
Ejection fraction (EF) quantifies the percentage of blood pumped out of the heart’s main pumping chamber, the left ventricle, with each contraction. It is calculated by dividing the volume of blood ejected from the ventricle per beat (stroke volume) by the total volume of blood in the ventricle before it contracts. For example, an ejection fraction of 60% indicates that 60% of the blood within the left ventricle is pushed out with each heartbeat. This measurement directly reflects the heart’s pumping efficiency.
How Ejection Fraction is Measured
Ejection fraction is commonly measured using various imaging techniques. Echocardiography, which utilizes sound waves to create images of the beating heart, is the most frequently employed and non-invasive method. This test shows how blood flows through the heart and its valves, allowing for the calculation of ejection fraction.
Other imaging modalities can also assess ejection fraction, including cardiac magnetic resonance imaging (MRI), nuclear medicine scans (MUGA or SPECT), and cardiac computed tomography (CT) scans. Echocardiography remains a primary tool due to its accessibility and non-invasive nature.
Understanding the Ejection Fraction Scale
A healthy heart typically exhibits a normal ejection fraction ranging from 50% to 70%. This range signifies that the heart is effectively pumping a sufficient amount of blood to meet the body’s demands with each contraction.
When the ejection fraction falls into the borderline range, typically between 40% and 49%, it may suggest early changes in heart function. This mid-range ejection fraction indicates that the heart’s pumping ability is slightly below normal. Individuals in this category might not experience heart failure symptoms at rest, but they could develop symptoms during physical activity.
An ejection fraction below 40% is considered reduced and often indicates heart failure or a heart muscle disease known as cardiomyopathy. The lower the percentage, the less blood the heart is pumping out, potentially leading to symptoms such as fatigue and shortness of breath.
In some cases, an ejection fraction exceeding 75% can also suggest a heart condition, such as hypertrophic cardiomyopathy, where the heart muscle thickens abnormally.
Common Causes of Altered Ejection Fraction
Several conditions can lead to a reduced ejection fraction. Coronary artery disease, characterized by narrowed arteries limiting blood supply to the heart, can weaken the heart muscle. A previous heart attack can also damage the heart muscle, impairing its pumping ability.
Long-term, uncontrolled high blood pressure forces the heart to work harder, which can eventually lead to a reduced ejection fraction. Heart valve problems, where valves do not function properly, can also increase the heart’s workload and affect its efficiency.
Cardiomyopathy, a disease that weakens the heart muscle, is another common cause. Other contributing factors include viral infections that damage the heart muscle, certain chemotherapy drugs, excessive alcohol consumption, and chronic conditions like diabetes and obesity.
The Importance of Monitoring Ejection Fraction
Medical professionals regularly monitor ejection fraction to gain insights into heart health. This measurement assists in diagnosing various heart conditions, including different types of heart failure. For instance, it helps distinguish between heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF).
Monitoring ejection fraction also helps guide treatment decisions, track the progression of heart disease, and assess the effectiveness of ongoing treatments. Regular assessment provides a clear picture of the heart’s functional changes, supporting informed clinical management.