Overview of Left Ventricular Ejection Fraction
The Left Ventricular Ejection Fraction (LVEF) is a key measure of how well the left side of your heart is working. Basically, it tells us what percentage of blood in your heart gets pumped out to the body with each heartbeat. This is calculated by looking at the volume of blood in your heart before it gets squeezed out (Stroke Volume) and comparing it with the total amount of blood in your heart just before it beats (End-Diastolic Volume). Remember, a healthy heart can’t push out 100% of the blood inside it with one beat, only a portion of it.
In a regular heartbeat:
LVEF = (Stroke Volume / End-Diastolic Volume) x 100
Normal levels for men and women, measured by an ultrasound of the heart, according to health standards set by the American Society of Echocardiography and the European Association of Cardiovascular Imaging are:
For men:
* 52% to 72% is the normal range
* 41% to 51% is mildly abnormal
* 30% to 40% is moderately abnormal
* Less than 30% is severely abnormal
For women:
* 54% to 74% is the normal range
* 41% to 53% is mildly abnormal
* 30% to 40% is moderately abnormal
* Less than 30% is severely abnormal
The American College of Cardiology breaks it down even further like this:
* Hyperdynamic (a very strong heartbeat) = LVEF greater than 70%
* Normal = LVEF 50% to 70%
* Mild dysfunction = LVEF 40% to 49%
* Moderate dysfunction = LVEF 30% to 39%
* Severe dysfunction = LVEF less than 30%
So if a doctor is doing a heart scan, they might tell you the numerical result (“your LVEF is 50%”) or they might provide qualitative information (“your heart function is normal”). In either case, it refers to the same thing, how much blood your heart is pumping out with each beat.
Why do People Need Left Ventricular Ejection Fraction
3>The accurate measurement of left ventricular ejection fraction (LVEF) – a term that describes how much blood your heart’s primary pumping chamber (the left ventricle) pumps out with each beat – is very important for managing patients with cardiovascular disease. LVEF assessment is also critical in predicting the likelihood of adverse outcomes in patients with congestive heart failure (a condition where your heart doesn’t pump blood as efficiently as it should), after a myocardial infarction (a fancy term for a heart attack), and after revamping the blood flow to the heart muscle (a surgical procedure known as revascularization).
The measurement of LVEF plays a crucial role in understanding how severe a decrease in the heart’s pumping or systolic function is. This helps healthcare professionals manage various heart-related diseases better.
Reasons why your doctor would want to measure your LVEF include:
- Finding out the structure and function of the left ventricle
- Checking how the left ventricle is working, both in specific areas (segmental) and as a whole (global), through qualitative (descriptive) and quantitative (numeric) methods
- Examining patients with signs that could suggest heart-related diseases
- Identifying the type of heart failure, whether it’s heart failure with preserved ejection fraction (when the heart muscle contracts normally but ventricles do not relax as they should) or reduced ejection fraction (when the heart muscle doesn’t contract efficiently and less oxygen-rich blood is pumped out to the body)
- Evaluating heart rhythm abnormalities to check for structural defects
- Checking heart function for patients exposed to potential heart-damaging treatments
- Evaluating before a medical procedure where the ability of the heart to pump blood might be a risk factor or a contraindication (a specific situation in which a procedure should not be used because it may be harmful to patient)
- Assessing congenital heart disease (heart problems present at birth)
- Evaluating valvular disorders (problems with the valves in the heart)
How is Left Ventricular Ejection Fraction performed
The Left Ventricular Ejection Fraction (LVEF), which is a measure of how well the heart is pumping out blood, can be calculated using several methods. Some methods use visuals for estimation, while others use more exact figures. Generally, the goal is to use a method that delivers the most accurate and precise results.
There are non-invasive methods that doctors can use to determine your LVEF, like echocardiography, Magnetic Resonance Imaging (MRI), Computed Tomography (CT), Gated Equilibrium Radionuclide Angiography (a type of scanning technology), and Gated Myocardial Perfusion Imaging using Single-Photon Emission Computed Tomography (SPECT) or Positron Emission Tomography (PET). Invasive procedures are also possible, like the use of contrast dye during catheterization to get more detailed images.
For echocardiography, there are various methods to measure LVEF. Some methods rely on dimensions, while others work with volume measurements. Usually, the two-dimensional technique, known as the Modified Simpson’s rule, is recommended. This method traces the heart border and divides it into multiple sections for precise measurement, which reduces the need for guessing the shape of the heart. However, there are other methods such as the modified Quinones that use linear measurements but are falling out of favor due to their reliance on fixed geometric assumptions about the heart.
Moreover, a three-dimensional echocardiography approach could provide more accurate measurements as it allows to see the entire heart without having to guess its form. This requires special probes and often a capture of several heartbeats to get the necessary data.
MRI can also be used to calculate LVEF. It involves the tracing of the heart border at both the end of contraction (end-systole) and relaxation (end-diastole) of the heart. Unlike other techniques, MRI does not require the use of potentially harmful radiation or contrast dye, which can be beneficial for some patients.
Contrarily, CT scanning requires contrast dye to differentiate between the blood and the heart wall. This makes it easier to outline the heart accurately. Despite providing good results, the use of CT can be limited due to the use of contrast material, which might not be suitable for all patients, especially those with poor kidney function or allergies to the contrast material.
Lastly, nuclear imaging can also be used to calculate LVEF, but this typically involves exposure to radiation. The two most common techniques used here are SPECT and PET scans.
In summary, there’s a variety of ways to calculate the LVEF, and the choice of method depends on the patient’s specific situation and the resources available. Each technique has its own benefits and drawbacks, so doctors will choose the one that best suits each individual case.
What Else Should I Know About Left Ventricular Ejection Fraction?
The left ventricular ejection fraction, or LVEF for short, is a measure of how well your heart is working. It tells us what percentage of blood in your heart’s left ventricle is pumped out with each beat. This is an important factor in predicting the risk of death from heart-related problems. In simple terms, the lower the LVEF, meaning less blood is pumped out, the higher the risk.
Professionals use the LVEF as a crucial factor for deciding whether someone needs an automatic defibrillator implant (a device that can correct abnormal heart rhythms). Studies have shown that people with a prior heart attack and an LVEF under 30% have a significantly lower risk of sudden cardiac death and overall death after getting a defibrillator. Therefore, LVEF plays a central role in guidelines deciding whether a defibrillator is recommended to prevent sudden cardiac death.
In patients with heart failure, statistics have shown a direct relationship between higher LVEF and lower mortality rates, up to an LVEF of 45%. Above this, increased LVEF doesn’t seem to further lower the risk. However, LVEF should not be viewed in isolation but should be considered along with other factors that indicate risk. The American College of Cardiology/American Heart Association always advocates for regular checking of LVEF to guide treatment in heart failure patients, but they do not currently clarify the relationship between LVEF and prognosis.
Furthermore, LVEF also holds significance when it comes to monitoring heart function during cancer treatments that may harm the heart (cardiotoxic chemotherapy). If a patient’s LVEF is less than 53% even before starting therapy, a consultation with a cardiologist is warranted to weigh the pros and cons. During treatment, if the LVEF decreases by more than 10% and remains under 53%, a referral to a heart-oncology unit is recommended to reconsider heart failure therapy and adjust cancer treatment strategy.
Lastly, in the case of patients with heart valve diseases, LVEF is also used in deciding treatment approaches. For patients with specific types of severe heart valve diseases who don’t show any symptoms, but their LVEF is less than 50% or equal to or less than 60%, valve replacement surgery is considered, depending on the type of valve disease.