How do you measure ejection fraction

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This content does not have an Arabic version. See more conditions. Request Appointment. Ejection fraction: What does it measure? Products and services. What does the term "ejection fraction" mean? Medications can treat it. If your ejection fraction is below 35 percent, your doctor will likely recommend other treatments, like an implantable cardioverter defibrillator or a pacemaker , to help regulate your heart rhythm. With this type of heart failure, you have a preserved, or normal, ejection fraction.

This may be due to a thickened heart muscle or heart muscle stiffness. It can lead to less blood being pumped from your heart to the rest of your body. Symptoms may include fatigue and shortness of breath during exercise. HFpEF can be the result of aging, diabetes, or high blood pressure.

As we age, our hearts do too. Heart walls thicken and lose some of their capacity to contract and relax as efficiently as they should. A high ejection fraction reading can indicate a heart condition known as hypertrophic cardiomyopathy.

This condition abnormally thickens parts of your heart muscle without an obvious cause. Hypertrophic cardiomyopathy is often genetic.

For a small number of people, hypertrophic cardiomyopathy can cause serious abnormal heart rhythms arrhythmias that require treatment. If you have a family history of hypertrophic cardiomyopathy, let your doctor know so they can monitor you over time.

There are a variety of treatment options for abnormal ejection fraction. Some of the most common treatments include:. With the modified Simpson method, the ventricle can be foreshortened on apical images, so that the true apex will not be imaged see Figure 5. This can lead to errors if apical function is discordant, as can happen with an apical infarct. Obese patients, patients with chronic obstructive pulmonary disease and patients with limited space between the ribs will often have poor image quality see Figure 6A.

The use of echocardiography contrast has been shown to improve LVEF determination in patients with poor acoustic windows and reduce inter-observer variability see Figure 6B. Several reconstruction techniques have been developed to acquire 3D data of the heart from which LV volumes can be calculated.

Unlike other echocardiographic methods, 3D methods make minimal assumptions of LV cavity shape. They have been shown to be less variable and more accurate than other echocardiographic methods, when compared with MRI as a reference standard.

However, the acoustic window needs to be of sufficient quality to allow the delineation of the entire LV cavity endocardial border. Because the image data are usually acquired over several heart beats, an ectopic beat or breathing during the imaging time will lead to artefacts which can alter the endocardial border see Figure 7 and different segments of the left ventricle will appear to contract at different times.

Also, LVEF is usually calculated using commercially available software that is semi-automated, requiring the user to manually assign certain points e. If the points are improperly assigned, the LVEF may be inaccurate.

The location of the endocardial border may also be incorrectly interpreted, either by the operator or the software due to poor definition, and a papillary muscle or trabecula may be interpreted as being the endocardial surface. The area of the tracing for each image slice is multiplied by the slice interval slice thickness plus image gap to determine a volume for that slice. The volumes of the slices are summed to determine an LV volume.

This method requires few assumptions of LV shape because the entire LV cavity is traced. Because of the high contrast resolution and high signal:noise ratio of MRI, the endocardial border is usually well defined. MRI is contraindicated in patients with implantable cardioverter defibrillators, most pacemakers and several other types of implanted devices.

Cardiac MRI requires multiple breath holds, and image quality may be poor in patients who cannot hold their breath. If the level of inspiration is different during the acquisition of different levels, segments of the LV may not be imaged while other segments may be imaged twice.

This may lead to variability in calculated volumes and LVEF. Because data are acquired over several cardiac cycles with ECG gating, image quality will be degraded in patients with cardiac arrhythmias or ectopic beats leading to decreased accuracy. In a study by Karamitsos et al. The automated methods usually rely on the differentiation of the LV cavity from the endocardium based on Hounsfield unit measurements.

As long as the contrast bolus timing is appropriate, there will be high contrast and spacial resolution resulting in a well defined endocardial border. Disadvantages of CT are the exposure of the patient to ionising radiation and the need for iodinated contrast material. Iodinated contrast material should be not be used in patients with iodinated contrast allergies — unless they have been pre-medicated to avoid any allergic reaction — and should be used judiciously in patients with poor renal function.

Also, variability in the selection of the ventricular basal segment will cause variability in LVEF calculation when using the Simpson method. Breathing during image acquisition can also lead to artefacts, which can reduce accuracy. Because of the need for intravenous IV contrast to delineate the endocardium, a problem that is unique to CT is the need for proper coordination of the timing of contrast injection and scanning.

LVEF can be calculated by several methods using different nuclear cardiac imaging techniques. Most commonly, planar images of the left ventricle are acquired for analysis, although SPECT images can also be acquired.

If planar imaging is used, a left anterior oblique projection with best separation of the left and right ventricle is acquired for LVEF calculation. Our online community of survivors and caregivers is here to keep you going no matter the obstacles. You can have a normal ejection fraction measurement and still have heart failure called HFpEF or heart failure with preserved ejection fraction. If the heart muscle has become so thick and stiff that the ventricle holds a smaller than usual volume of blood, it might still seem to pump out a normal percentage of the blood that enters it.

A ejection fraction measurement under 40 percent may be evidence of heart failure or cardiomyopathy. Instead, it may indicate damage, perhaps from a previous heart attack. In severe cases, ejection fraction can be very low. Learn ways to improve your low ejection fraction.