In cardiovascular physiology, ejection fraction (Ef) is the fraction of blood pumped out of a ventricle with each heart beat. This is an article about the rock music band "Circulatory System" Blood is a specialized Bodily fluid that delivers necessary substances to the body's cells such as nutrients and oxygen—and transports Waste products In the Heart, a ventricle is a heart chamber which collects Blood from an atrium (another heart chamber that is smaller than a ventricle and Cardiac cycle is the term referring to all or any of the events related to the flow of blood that occur from the beginning of one heartbeat to the beginning of the next The term ejection fraction applies to both the right and left ventricles; one can speak equally of the left ventricular ejection fraction (LVEF) and the right ventricular ejection fraction (RVEF). Without a qualifier, the term ejection fraction refers specifically to that of the left ventricle. Its reverse operation is the injection fraction. Injection fraction is the inverse operation of the Myocardial Ejection fraction.
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Overview
By definition, the volume of blood within a ventricle immediately before a contraction is known as the end-diastolic volume. In Cardiovascular physiology, end-diastolic volume ( EDV) is the volume of Blood in a ventricle at the end of filling ( Diastole) Similarly, the volume of blood left in a ventricle at the end of contraction is end-systolic volume. End-systolic volume ( ESV) is the volume of Blood in the left ventricle at the end of contraction or Systole, and the beginning of filling or Diastole The difference between end-diastolic and end-systolic volumes is the stroke volume, the volume of blood ejected with each beat. Stroke volume (SV is the volume of Blood pumped by the right/ Left ventricle of the heart in one contraction. Ejection fraction (Ef) is the fraction of the end-diastolic volume that is ejected with each beat; that is, it is stroke volume (SV) divided by end-diastolic volume (EDV):
Normal values
In a healthy 70-kg (154-lb) man, the SV is approximately 70 ml and the left ventricular EDV is 120 ml, giving an ejection fraction of 70/120, or 58%. Right ventricular volumes being roughly equal to those of the left ventricle, the ejection fraction of the right ventricle is normally equal to that of the left ventricle within narrow limits.
Healthy individuals typically have ejection fractions greater than 0. 55. However, normal values depend upon the modality being used to calculate the ejection fraction. Damage to the muscle of the heart (myocardium), such as that sustained during myocardial infarction or in cardiomyopathy, impairs the heart's ability to eject blood and therefore reduces ejection fraction. Myocardium is the muscular tissue of the Heart. Relationship to other layers The other tissues of the heart are the Endocardium Myocardial infarction ( MI or AMI for acute myocardial infarction) also known as a heart attack, occurs when the blood supply Cardiomyopathy, which literally means "heart muscle disease" is the deterioration of the function of the Myocardium (i This reduction in the ejection fraction can manifest itself clinically as heart failure. Heart failure is a Cardiac condition that occurs when a problem with the structure or function of the Heart impairs its ability to supply The ejection fraction is one of the most important predictors of prognosis; those with significantly reduced ejection fractions typically have a poorer prognoses. Prognosis (older Greek πρόγνωσις modern Greek πρόγνωση - literally fore-knowing foreseeing) is a medical term denoting the
Measurement
Ejection fraction is commonly measured by echocardiography, in which the volumes of the heart's chambers are measured during the cardiac cycle. An echocardiogram is a Sonography of the Heart. Also known as a cardiac ultrasound it uses standard ultrasound techniques to image two-dimensional slices of Cardiac cycle is the term referring to all or any of the events related to the flow of blood that occur from the beginning of one heartbeat to the beginning of the next Ejection fraction can then be obtained by dividing stroke volume by end-diastolic volume as described above.
Other methods of measuring ejection fraction include cardiac MRI, fast scan cardiac computed axial tomography (CT) imaging, ventriculography, Gated SPECT, and the MUGA scan. Computed tomography (CT is a Medical imaging method employing Tomography. Cerebral ventriculography is a medical procedure developed by Walter Dandy, and designed to enable visualization of structures inside the skull Gated SPECT - A Nuclear medicine imaging SPECT (Single Photon Emission Computed Tomography procedure where the ECG (Electrocardiogram guides the acquisition A MUGA scan (Multi Gated Acquisition Scan is a Nuclear medicine test to evaluate the function of the Heart Ventricles. A MUGA scan involves the injection of a radioisotope into the blood and detecting its flow through the left ventricle. A radionuclide is an Atom with an unstable nucleus, which is a nucleus characterized by excess energy which is available to be imparted either to a newly-created The historical gold standard for the measurement of ejection fraction is ventriculography. In Medicine, a gold standard test or criterion standard test is a Diagnostic test or benchmark that is regarded as definitive
See also
References
- Berne, Robert M. Cardiac output (Q is the volume of blood being pumped by the Heart, in particular by a ventricle in a minute Heart failure is a Cardiac condition that occurs when a problem with the structure or function of the Heart impairs its ability to supply , Levy, Matthew N. (2001). Cardiovascular Physiology. Philadelphia, PA: Mosby.
- Boron, Walter F. , Boulpaep, Emile L. (2005). Medical Physiology: A Cellular and Molecular Approach. Philadelphia, PA: Elsevier/Saunders.
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