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Ejection fraction

Related Terms

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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.
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Contributing Factors

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Technique

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Theory/Evidence

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Author Information

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References

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

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The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.