Left ventricular ejection fraction

Related Terms

3D-imaging, 3-dimensional echocardiography, angina pectoris, cardiac catheterization, cardiac CT imaging, cardiac ECHO, cardiac MRI, cardiac ultrasound, cardiomyopathy, chronic ischemic heart disease, combined systolic and diastolic heart failure, computed tomography, contraction, diastolic, diastolic heart failure, Doppler echocardiography, ECG, ECHO, echocardiogram, echocardiography, echocardiography probe, echocardiography transducer, EF, Ef, EKG, electrocardiogram, electrocardiography, end diastolic volume, end systolic volume, gated blood pool imaging, heart attack, heart beat, heart failure, heart function, heart muscle function, heart strength, high blood pressure, hypertension, injection fraction, left ventricle, left ventricular contractility, left ventricular ejection fraction, left ventricular ejection time, left ventricular function, LVEF/LVET, LVET, magnetic resonance imaging, MUGA scan, multi gated acquisition scan, nuclear stress test, PEP, plethysmography, pre-ejection period, primary pulmonary hypertension, pulsed or continuous wave Doppler ultrasound, radionuclide angiography, right ventricular ejection fraction, sonogram, stroke volume, systolic, systolic heart failure, systolic time intervals, TEE, TOE, transesophageal echocardiogram, transthoracic echocardiogram, TTE, ventriculography.

Background

The heart has four chambers, the right and left atrium, and the right and left ventricle. Oxygen-poor blood from the body enters the right atrium, where it is delivered to the right ventricle to be pumped to the lungs to receive oxygen. Once the blood receives oxygen, it enters the left atrium, and is delivered to the left ventricle, which pumps it to the rest of the body. In the heart are four valves that prevent blood flowing backwards. Changes in the proper function of these valves can occur, causing related valvular disorders, such as mitral valve (the valve between the left atrium and left ventricle) prolapse (MVP). The aortic valve is responsible for preventing reverse blood flow so that blood leaves the left ventricle to enter the artery. The time between the opening of the aortic valve for release of blood from the left ventricle to closure of the valve is known as the left ventricular ejection time (LVET). With some diseases of the heart, the LVET may be reduced.
Immediately before a heart contraction there is a certain volume of blood within the ventricle. This is called the end-diastolic volume (EDV). After the contraction, there is a certain amount of blood left in the ventricle and this is called the end-systolic volume (ESV). The difference between these (EDV-ESV) is the stroke volume (SV). The ejection fraction (EF) is the SV divided by the EDV (SV/EDV), and is often expressed as a percentage, with normal values being 50-70%. EF can be defined as the amount of blood pumped by the heart into circulation with each heartbeat. Although EF can refer to either the left ventricle or the right ventricle, it is the left ventricular function that is more commonly investigated, because it is the left ventricle that pumps the blood to the body.
LVET is used along with the EF to understand whether the ventricle is contracting normally. When the heart muscle is damaged, the EF and/or ejection times may be reduced. Conditions that may damage heart muscle and cause reduced EF include myocardial infarction or cardiomyopathy. A reduced EF is known as systolic heart failure. Heart failure may occur in the absence of reduced EF (diastolic heart failure). Reduction in LVET is associated with various disorders, such as fibromyalgia, cardiomyopathy, angina, obesity, hemodialysis, and high blood pressure. It is also related to the use of certain medications and stressors such as heat and exercise. LVET and EF values may be used to understand whether a disease is getting worse or staying the same.
Higher EF may also be a problem (>75%) and may indicate hypertrophic cardiomyopathy, a disorder in which the heart muscle becomes thickened. EF values may or may not be related to any symptoms a person is feeling.
The EF of the heart is commonly measured using echocardiography. Other examples of methods of measurement include cardiac magnetic resonance imaging (MRI), cardiac computed tomography (CT) imaging, multigated acquisition (MUGA) scan, cardiac catheterization, and ventriculography. Types of echocardiography include transesophageal echocardiography (TOE), transthoracic echocardiography (TTE or TEE), and 3-dimensional echocardiography. The test is chosen by an appropriate medical practitioner. The practitioner will be able to read, understand, and explain the results of the test.
Once diagnosed with reduced EF, both pharmaceutical and non-pharmaceutical treatments may be used. Examples of non-pharmaceutical treatments include increasing exercise, quitting smoking, reducing alcohol intake, losing weight, and changing diet. Pharmaceutical treatments may include the use of ACE (angiotensin converting enzyme) inhibitors and beta blockers. No treatment should be initiated without the approval of a healthcare provider.

Theory / Evidence

The ejection fraction (EF) value is one of the most important predictors of survival in patients with left ventricular dysfunction.
Reduced EF is linked with systolic heart failure, usually associated with diseases, like atherosclerosis, cardiomyopathy, and high blood pressure. A reduction in LVET (left ventricular ejection time) is associated with various disorders, including, but not limited to fibromyalgia, Duchenne's cardiomyopathy, angina and ischemic heart disease, obesity, hemodialysis, and hypertension (high blood pressure). Reduced LVET is also related to the use of certain medications, such as antiadrenergic agents, adriamycin, propanolol, and theophylline, and stressors such as heat and exercise. Reduced EF is also a major risk factor for mitral valve prolapse (MVP) complications.
The most common medications for treatment of reduced EF include ACE (angiotensin converting enzyme) inhibitors and beta blockers. These agents may often improve EF values but do not always improve the way the patient feels. Beta-blockers are beta adrenergic receptor antagonists. These agents reduce the effect of epinephrine, otherwise known as adrenaline, on the heart. Science suggests that mortality may be decreased in patients properly treated for reduced EF. Beta-blocker treatment improves left ventricular function in heart failure patients, irrespective of the cause of the failure. However, although all beta-blockers improved left ventricular function, some were more effective for reducing mortality. This suggests that beta-blockers also affect survival by mechanisms independent of left ventricular function. ACE inhibitors are commonly used to reduce blood pressure, which may have cardioprotective effects, but may also have benefits in patients with cardiovascular disease, by a mechanism independent of blood pressure lowering.
Lifestyle changes to reduce progression of heart failure associated with reduced EF include blood pressure reduction, smoking cessation, healthy weight maintenance, reduction of alcohol intake, and dietary changes (e.g., sodium reduction).
LVET is used in the prognosis of primary pulmonary hypertension, and a marked decrease is associated with immediate death or clinical deterioration. Impaired left ventricular function (EF and pre-ejection period (PEP)/LVET ratio) may occur early in the clinical course of non-insulin-dependent diabetes.
Improvement in left ventricular function, associated with increased LVET or decreased PEP/LVET is associated with use of CoQ10 in patients with myocardial failure showing an insufficient response to classical therapy with diuretics and digitalis. According to a review, hawthorn may also increase left ventricular EF.

Author information

This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

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Technique

General: The ejection fraction (EF) of the heart is commonly measured using echocardiography. Other methods of measurement include cardiac magnetic resonance imaging (MRI), cardiac computerized tomography (CT) imaging, MUGA scan (multigated acquisition scan) or ventriculography, and cardiac catheterization.
Echocardiography: EF is generally measured using echocardiography. Various types of echocardiography exist, including transesophageal echocardiography (TOE), transthoracic echocardiography (TTE or TEE), and 3-dimensional echocardiography.
Echocardiography is a non-invasive ultrasound test. Transthoracic ECHO is a common test during which the ultrasound instrument is held over the patient's chest. In transesophageal ECHO, the instrument is placed in the patient's esophagus. 3-Dimensional ECHO allows for a 3-D picture of the heart and its chambers. In each case, a sound wave bounces off the heart creating images of the valves and chambers. This test can allow for the determination of the thickness of the heart muscle and can determine how much of the blood is being pumped out of the body.
Multigated acquisition (MUGA) scan or ventriculography: Radioactive substances are injected into the bloodstream using a needle. These radionuclides are short-lived so they do not stay in the body for a long time. The radionuclides go to the heart where they can be seen using computer-generated pictures. This allows for the determination of how well the chambers are working by using mathematical models to determine the left ventricular function.
Computed tomography (CT): A cross-sectional 3-dimensional image of the heart is made during the CT scan. Thus, the volume of blood can be measured in order to determine the EF.
Other: Less commonly used techniques for determination of the EF include cardiac MRI and cardiac catheterization (a catheter or thin flexible tube is inserted into the vein to go to the heart).

Contributing factors

General: Left ventricular function, including ejection time and ejection fraction (EF), is a measure of the health and strength of the heart muscle. Changes in EF or abnormal values may be an indication of disease and may be very useful in making diagnostic, prognostic, and therapeutic determinations.
Factors that may contribute to reduced left ventricular function include high blood pressure, blocked arteries, heart disease, medications, and stress.
Non-modifiable factors:
Genetics: Heart defects present since birth (otherwise known as congenital heart disease) may increase the risk of heart failure, including systolic heart failure, which is determined based on a reduction in left ventricular EF.
Modifiable lifestyle factors:
Obesity: Systolic heart failure and reductions in EF are associated with coronary artery disease, past myocardial infarction (heart attack), diabetes, high cholesterol, and high blood pressure; the risk of all of these is increased with obesity.
Physical activity: Systolic heart failure and reductions in EF are associated with coronary artery disease, past myocardial infarction (heart attack), diabetes, high cholesterol, and high blood pressure; the risk of all of these is increased in sedentary individuals. However, once diagnosed with reduced EF, exercise programs should be discussed with the healthcare practitioner to either modify the existing exercise program or initiate one appropriate for the condition.
Smoking: Systolic heart failure and reductions in EF are associated with coronary artery disease, past myocardial infarction (heart attack), high cholesterol, and high blood pressure; the risk of all of these is increased with smoking.
Other factors:
Disease: Systolic heart failure and reductions in EF are associated with coronary artery disease, past myocardial infarction (heart attack), cardiomyopathy, diabetes, abnormal heart valves, congenital heart disease, severe lung disease, high cholesterol, and high blood pressure.