Ejection fraction

Jump to navigation Jump to search

WikiDoc Resources for Ejection fraction

Articles

Most recent articles on Ejection fraction

Most cited articles on Ejection fraction

Review articles on Ejection fraction

Articles on Ejection fraction in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Ejection fraction

Images of Ejection fraction

Photos of Ejection fraction

Podcasts & MP3s on Ejection fraction

Videos on Ejection fraction

Evidence Based Medicine

Cochrane Collaboration on Ejection fraction

Bandolier on Ejection fraction

TRIP on Ejection fraction

Clinical Trials

Ongoing Trials on Ejection fraction at Clinical Trials.gov

Trial results on Ejection fraction

Clinical Trials on Ejection fraction at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Ejection fraction

NICE Guidance on Ejection fraction

NHS PRODIGY Guidance

FDA on Ejection fraction

CDC on Ejection fraction

Books

Books on Ejection fraction

News

Ejection fraction in the news

Be alerted to news on Ejection fraction

News trends on Ejection fraction

Commentary

Blogs on Ejection fraction

Definitions

Definitions of Ejection fraction

Patient Resources / Community

Patient resources on Ejection fraction

Discussion groups on Ejection fraction

Patient Handouts on Ejection fraction

Directions to Hospitals Treating Ejection fraction

Risk calculators and risk factors for Ejection fraction

Healthcare Provider Resources

Symptoms of Ejection fraction

Causes & Risk Factors for Ejection fraction

Diagnostic studies for Ejection fraction

Treatment of Ejection fraction

Continuing Medical Education (CME)

CME Programs on Ejection fraction

International

Ejection fraction en Espanol

Ejection fraction en Francais

Business

Ejection fraction in the Marketplace

Patents on Ejection fraction

Experimental / Informatics

List of terms related to Ejection fraction

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

In cardiovascular physiology, ejection fraction (Ef) is the fraction of blood pumped out of a ventricle with each heart beat. 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.

By definition, the volume of blood within a ventricle immediately before a contraction is known as the end-diastolic volume. Similarly, the volume of blood left in a ventricle at the end of contraction is end-systolic volume. The difference between end-diastolic and end-systolic volumes is the stroke volume, the volume of blood ejected with each beat. 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):

<math>E_f = \frac{SV}{EDV} = \frac{EDV - ESV}{EDV}</math>

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. This reduction in the ejection fraction can manifest itself clinically as heart failure. The ejection fraction is one of the most important predictors of prognosis; those with significantly reduced ejection fractions typically have a poorer prognoses.

Measurement

Ejection fraction is commonly measured by echocardiography, in which the volumes of the heart's chambers are measured during the cardiac cycle. 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. A MUGA scan involves the injection of a radioisotope into the blood and detecting its flow through the left ventricle. The historical gold standard for the measurement of ejection fraction is ventriculography.

ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias (DO NOT EDIT) [1]

Left Ventricular Function and Imaging Recommendations

Class I
"1 Echocardiography is recommended in patients with ventricular arrhythmias who are suspected of having structural heart disease. (Level of Evidence: B) "
"2 Echocardiography is recommended for the subset of patients at high risk for the development of serious ventricular arrhythmias or SCD, such as those with dilated, hypertrophic, or RV cardiomyopathies, AMI survivors, or relatives of patients with inherited disorders associated with SCD. (Level of Evidence: B) "
"3 Exercise testing with an imaging modality (echocardiography or nuclear perfusion [single-photon emission computed tomography (SPECT)]) is recommended to detect silent ischemia in patients with ventricular arrhythmias who have an intermediate probability of having CHD by age, symptoms, and gender and in whom ECG assessment is less reliable because of digoxin use, LVH, greater than 1-mm ST-segment depression at rest, WPW syndrome, or LBBB. (Level of Evidence: B) "
"4 Pharmacological stress testing with an imaging modality (echocardiography or myocardial perfusion SPECT) is recommended to detect silent ischemia in patients with ventricular arrhythmias who have an intermediate probability of having CHD by age, symptoms, and gender and are physically unable to perform a symptomlimited exercise test. (Level of Evidence: B) "
Class IIa
"1 MRI, cardiac computed tomography (CT), or radionuclide angiography can be useful in patients with ventricular arrhythmias when echocardiography does not provide accurate assessment of LV and RV function and/or evaluation of structural changes. (Level of Evidence: B)"
"2 Coronary angiography can be useful in establishing or excluding the presence of significant obstructive CHD in patients with life-threatening ventricular arrhythmias or in survivors of SCD, who have an intermediate or greater probability of having CHD by age, symptoms, and gender. (Level of Evidence: C)"
"3 LF imaging can be useful in patients undergoing biventricular pacing. (Level of Evidence: C) "

See also

References

  • Berne, Robert M., Levy, Matthew N. (2001). Cardiovascular Physiology. Philadelphia, PA: Mosby. ISBN 0-323-01127-6.
  • Boron, Walter F., Boulpaep, Emile L. (2005). Medical Physiology: A Cellular and Molecular Approach. Philadelphia, PA: Elsevier/Saunders. ISBN 1-4160-2328-3.

Template:WikiDoc Sources