Ejection fraction

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The ejection fraction  (EF; Latin e- = out, iacere = throw, fractio = fragment, portion) or ejection fraction (also expulsion fraction ) is a measure of the heart function . Since when the heart muscle contracts, not the entire volume of blood is expelled from the chamber, but rather a certain part remains, the proportion of the expelled volume in the end-diastolic filling volume can provide information about the condition of the cardiovascular system.

Each of the four heart cavities (Latin: cavum cordis ) has its own ejection fraction with each heartbeat . With each heartbeat, the end-diastolic filling volumes are different in all cardiac cavities, because the atria and ventricles do not have exactly the same volume (especially evident in asymmetric dilated cardiomyopathy ). However, the stroke volume as the product of these two parameters must form a constant in all four cavities for each heartbeat in order to prevent backflow in the bloodstream . This relativizes the informative value of the ejection fraction as a usual measure for the severity of a heart failure . Because of the great importance of the left ventricle , the EF of the left ventricle (as LVEF) is almost exclusively given in cardiology .

With heart valve defects and with atrial septal defects , ventricular septal defects or with a shunt (Latin: vitium cordis ), blood backflows in the heart cavities against the intended flow direction with every heartbeat; one speaks of the flow reversal ( reverse flow ), of pendulum volume and of regurgitation. So the measured gross injection fraction would have to be correctly distinguished from the effective net injection fraction. The difference would be the regurgitation fraction . Especially in these patients, too, the gross injection fraction is not a suitable measure of the severity of their heart failure.

The ejection fraction describes the proportion of blood ejected from the heart during a contraction in relation to the total blood volume in the heart chamber. It is defined as the proportion of stroke volume  (SV) in relation to the end diastolic  volume (EDV). In healthy people, with a normal end-diastolic volume of around 120 ml and with a physiological stroke volume of around 80 ml, it is around 67%.

The stroke volume is the difference between the end diastolic and end systolic  volume (ESV):

Determination of the ejection fraction in ultrasound using the Simpson method
Determination of the ejection fraction in ultrasound in M-mode according to Teichholz
(less precise than the Simpson method)

The ejection fraction can be measured using various test methods, in descending order of frequency:

In clinical practice, the assessment of the ejection fraction is often based on the visual impression; this is considered sufficient with subjectively normal pump function. If the pump function is restricted, a quantitative determination should be made using the Simpson disk summation method ; the quantification using M-mode according to Teichholz is regarded as too imprecise.

Reference values

The European and American Society for Echocardiography give identical reference values ​​for the assessment of the global pump function based on the ejection fraction.

Ejection fraction Pump function
52-72% normal
41-51% slightly restricted
30-40% moderately restricted
<30% highly restricted

Clinical significance

A reduced ejection fraction is used as an objectifiable parameter in addition to the clinical symptoms for diagnosing heart failure. In asymptomatic patients, an EF <35–40% defines the presence of left ventricular dysfunction ( NYHA I ) and thus the need for drug therapy for heart failure with an ACE inhibitor .

With simultaneous expansion of the heart chambers (dilation) and disturbance of the spread of excitation (QRS> 120 ms) or after myocardial infarction, the implantation of a CRT system with defibrillator function is indicated in cases of EF <35% .

A reduced ejection fraction, along with other parameters such as clinical symptoms and laboratory markers, is an indicator of a poor prognosis for heart failure.

Individual evidence

  1. ^ "Reduction of the myocardial wall tension", Frankfurt am Main, no year, page 48.
  2. SD Solomon (2007) et al .: Essential Echocardiography , page 93, ISBN 1-58829-322-X , ISBN 978-1-58829-322-0
  3. a b T. Buck et al. (2009) Manual for the indication and implementation of echocardiography . In: Clinical Research in Cardiology Suppl 4: 3–51]
  4. LE Teichholz, T. Kreulen, MV Herman, R. Gorlin (1976): Problems in echocardiographic volume determinations: echocardiographic-angiographic correlations in the presence of absence of asynergy . At J Cardiol. 37 (1): 7-11.
  5. Roberto M. Lang, Luigi P. Badano, Victor Mor-Avi et al. (2015): Recommendations for Cardiac Chamber Quantification by Echocardiography in Adults: An Update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging (J Am Soc Echocardiogr 2015; 28: 1-39.)
  6. National Health Care Guideline for Chronic Heart Failure (2009), accessed on November 5, 2011
  7. Dickstein K. et al. 2010 Focused Update of ESC Guidelines on device therapy in heart failure ( Memento from January 12, 2012 in the Internet Archive ) (PDF; 359 kB). European Heart Journal 31: 2677-2687
  8. Dickstein K. et al. (2008) ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure ( Memento from January 12, 2012 in the Internet Archive ). European Heart Journal; 29, 2388-2442. Table 17. Retrieved November 5, 2011