Ejection fraction

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An ejection fraction (EF) is the volumetric fraction (or portion of the total) of fluid (usually blood) ejected from a chamber (usually the heart) with each contraction (or heartbeat). It can refer to the cardiac atrium, [1] ventricle, [2] gall bladder, [3] or leg veins, [4] although if unspecified it usually refers to the left ventricle of the heart. EF is widely used as a measure of the pumping efficiency of the heart and is used to classify heart failure types. It is also used as an indicator of the severity of heart failure, although it has recognized limitations. [5]

Contents

The EF of the left heart, known as the left ventricular ejection fraction (LVEF), is calculated by dividing the volume of blood pumped from the left ventricle per beat (stroke volume) by the volume of blood present in the left ventricle at the end of diastolic filling (end-diastolic volume). LVEF is an indicator of the effectiveness of pumping into the systemic circulation. The EF of the right heart, or right ventricular ejection fraction (RVEF), is a measure of the efficiency of pumping into the pulmonary circulation. A heart which cannot pump sufficient blood to meet the body's requirements (i.e., heart failure) will often, but not invariably, have a reduced ventricular ejection fraction. [6]

In heart failure, the difference between heart failure with a reduced ejection fraction, and heart failure with a preserved ejection fraction, is significant, because the two types are treated differently.

Measurement

Modalities applied to measurement of ejection fraction is an emerging field of medical mathematics and subsequent computational applications. The first common measurement method is echocardiography, [7] [8] although cardiac magnetic resonance imaging (MRI), [8] [9] cardiac computed tomography, [8] [9] ventriculography and nuclear medicine (gated SPECT and radionuclide angiography) [8] [10] scans may also be used. Measurements by different modalities are not easily interchangeable. [11] Historically, the gold standard for measurement of the ejection fraction was ventriculography, [12] but cardiac MRI is now considered the best method. [13] Prior to these more advanced techniques, the combination of electrocardiography and phonocardiography was used to accurately estimate ejection fraction. [14]

Physiology

Normal values

In a healthy 70-kilogram (150 lb) man, the stroke volume is approximately 70 mL, and the left ventricular end-diastolic volume (EDV) is approximately 120 mL, giving an estimated ejection fraction of 70⁄120, or 0.58 (58%). Healthy individuals typically have ejection fractions between 50% and 65%, [15] although the lower limits of normality are difficult to establish with confidence. [16]

Ventricular volumes
MeasureRight ventricleLeft ventricle
End-diastolic volume 144 mL (± 23 mL) [17] 142 mL (± 21 mL) [18]
End-diastolic volume / body surface area (mL/m2)78 mL/m2 (± 11 mL/m2) [17] 78 mL/m2 (± 8.8 mL/m2) [18]
End-systolic volume 50 mL (± 14 mL) [17] 47 mL (± 10 mL) [18]
End-systolic volume / body surface area (mL/m2)27 mL/m2 (± 7 mL/m2) [17] 26 mL/m2 (± 5.1 mL/m2) [18]
Stroke volume 94 mL (± 15 mL) [17] 95 mL (± 14 mL) [18]
Stroke volume / body surface area (mL/m2)51 mL/m2 (± 7 mL/m2) [17] 52 mL/m2 (± 6.2 mL/m2) [18]
Ejection fraction 66% (± 6%) [17] 67% (± 4.6%) [18]
Heart rate 60–100 bpm [19] 60–100 bpm [19]
Cardiac output 4.0–8.0 L/minute [20] 4.0–8.0 L/minute [20]

Pathophysiology

Heart failure categories

Damage to heart muscle (myocardium), such as occurring following myocardial infarction or cardiomyopathy, compromises the heart's performance as an efficient pump and may reduce ejection fraction. This broadly understood distinction marks an important determinant between ischemic vs. nonischemic heart failure. Such reduction in the EF can manifest itself as heart failure. The 2021 European Society of Cardiology guidelines for the diagnosis and treatment of acute and chronic heart failure subdivided heart failure into three categories on the basis of LVEF: [21]

  1. normal or preserved LVEF [≥50%] (HFpEF)
  2. moderately reduced LVEF [in the range of 41–49%] (HFmrEF)
  3. reduced LVEF [≤40%] (HFrEF)]

A chronically low ejection fraction less than 30% is an important threshold in qualification for disability benefits in the US. [22]

Calculation

By definition, the volume of blood within a ventricle at the end of diastole is the end-diastolic volume (EDV). Likewise, the volume of blood left in a ventricle at the end of systole (contraction) is the end-systolic volume (ESV). The difference between EDV and ESV is the stroke volume (SV). The ejection fraction 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): [23]

Where the stroke volume is given by:

EF is inherently a relative measurement—as is any fraction, ratio, or percentage, whereas the stroke volume, end-diastolic volume or end-systolic volume are absolute measurements.[ citation needed ]

History

William Harvey described the basic mechanism of the systemic circulation in his 1628 De motu cordis . It was initially assumed that the heart emptied completely during systole. [24] However, in 1856 Chauveau and Faivre [25] observed that some fluid remained in the heart after contraction. This was confirmed by Roy and Adami in 1888. [26] In 1906, Henderson [27] estimated the ratio of the volume discharged in systole to the total volume of the left ventricle to be approximately 2/3. In 1933, Gustav Nylin proposed that the ratio of the heart volume/stroke volume (the reciprocal of ejection fraction) could be used as a measure of cardiac function. [28] In 1952, Bing and colleagues used a minor modification of Nylin's suggestion (EDV/SV) to assess right ventricular function using a dye dilution technique. [29] Exactly when the relationship between end diastolic volume and stroke volume was inverted into its current form is unclear. Holt calculated the ratio SV/EDV and noted that '...The ventricle empties itself in a "fractional" manner, approximately 46 per cent of its end-diastolic volume being ejected with each stroke and 54 per cent remaining in the ventricle at the end of systole'. [30]

In 1962, Folse and Braunwald used the ratio of forward stroke volume/EDV and observed that "estimations of the fraction of the left ventricular end-diastolic volume that is ejected into the aorta during each cardiac cycle, as well as of the ventricular end-diastolic and residual volumes, provide information that is fundamental to a hemodynamic analysis of left ventricular function". [31] Elliott, Lane and Gorlin used the term "ejection fraction" in a conference paper abstract published in January 1964. [32] In 1965, Bartle et al. used the term ejected fraction for the ratio SV/EDV, [33] and the term ejection fraction was used in two review articles in 1968 suggesting a wide currency by that time. [2] [34]

Related Research Articles

<span class="mw-page-title-main">Systole</span> Part of the cardiac cycle when a heart chamber contracts

Systole is the part of the cardiac cycle during which some chambers of the heart contract after refilling with blood.

<span class="mw-page-title-main">Heart failure</span> Failure of the heart to provide sufficient blood flow

Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF typically presents with shortness of breath, excessive fatigue, and bilateral leg swelling. The severity of the heart failure is mainly decided based on ejection fraction and also measured by the severity of symptoms. Other conditions that have symptoms similar to heart failure include obesity, kidney failure, liver disease, anemia, and thyroid disease.

<span class="mw-page-title-main">Ventricle (heart)</span> Chamber of the heart

A ventricle is one of two large chambers located toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the upper heart that is smaller than a ventricle. Interventricular means between the ventricles, while intraventricular means within one ventricle.

<span class="mw-page-title-main">Echocardiography</span> Medical imaging technique of the heart

Echocardiography, also known as cardiac ultrasound, is the use of ultrasound to examine the heart. It is a type of medical imaging, using standard ultrasound or Doppler ultrasound. The visual image formed using this technique is called an echocardiogram, a cardiac echo, or simply an echo.

In cardiovascular physiology, stroke volume (SV) is the volume of blood pumped from the ventricle per beat. Stroke volume is calculated using measurements of ventricle volumes from an echocardiogram and subtracting the volume of the blood in the ventricle at the end of a beat from the volume of blood just prior to the beat. The term stroke volume can apply to each of the two ventricles of the heart, although when not explicitly stated it refers to the left ventricle and should therefore be referred to as left stroke volume (LSV). The stroke volumes for each ventricle are generally equal, both being approximately 90 mL in a healthy 70-kg man. Any persistent difference between the two stroke volumes, no matter how small, would inevitably lead to venous congestion of and/or shunt between the systemic and the pulmonary circulation.

In cardiovascular physiology, end-diastolic volume (EDV) is the volume of blood in the right or left ventricle at end of filling in diastole which is amount of blood present in ventricle at the end of diastole. Because greater EDVs cause greater distention of the ventricle, EDV is often used synonymously with preload, which refers to the length of the sarcomeres in cardiac muscle prior to contraction (systole). An increase in EDV increases the preload on the heart and, through the Frank-Starling mechanism of the heart, increases the amount of blood ejected from the ventricle during systole.

End-systolic volume (ESV) is the volume of blood in a ventricle at the end of contraction, or systole, and the beginning of filling, or diastole.

<span class="mw-page-title-main">Afterload</span> Pressure in the wall of the left ventricle during ejection

Afterload is the pressure that the heart must work against to eject blood during systole. Afterload is proportional to the average arterial pressure. As aortic and pulmonary pressures increase, the afterload increases on the left and right ventricles respectively. Afterload changes to adapt to the continually changing demands on an animal's cardiovascular system. Afterload is proportional to mean systolic blood pressure and is measured in millimeters of mercury.

<span class="mw-page-title-main">Diastole</span> Part of the cardiac cycle

Diastole is the relaxed phase of the cardiac cycle when the chambers of the heart are refilling with blood. The contrasting phase is systole when the heart chambers are contracting. Atrial diastole is the relaxing of the atria, and ventricular diastole the relaxing of the ventricles.

<span class="mw-page-title-main">Aortic regurgitation</span> Medical condition

Aortic regurgitation (AR), also known as aortic insufficiency (AI), is the leaking of the aortic valve of the heart that causes blood to flow in the reverse direction during ventricular diastole, from the aorta into the left ventricle. As a consequence, the cardiac muscle is forced to work harder than normal.

<span class="mw-page-title-main">Mitral regurgitation</span> Form of valvular heart disease

Mitral regurgitation (MR), also known as mitral insufficiency or mitral incompetence, is a form of valvular heart disease in which the mitral valve is insufficient and does not close properly when the heart pumps out blood. It is the abnormal leaking of blood backwards – regurgitation from the left ventricle, through the mitral valve, into the left atrium, when the left ventricle contracts. Mitral regurgitation is the most common form of valvular heart disease.

<span class="mw-page-title-main">Radionuclide angiography</span> Nuclear medicine imaging the ventricles of the heart

Radionuclide angiography is an area of nuclear medicine which specialises in imaging to show the functionality of the right and left ventricles of the heart, thus allowing informed diagnostic intervention in heart failure. It involves use of a radiopharmaceutical, injected into a patient, and a gamma camera for acquisition. A MUGA scan involves an acquisition triggered (gated) at different points of the cardiac cycle. MUGA scanning is also called equilibrium radionuclide angiocardiography, radionuclide ventriculography (RNVG), or gated blood pool imaging, as well as SYMA scanning.

Pulsus paradoxus, also paradoxic pulse or paradoxical pulse, is an abnormally large decrease in stroke volume, systolic blood pressure and pulse wave amplitude during inspiration. Pulsus paradoxus is not related to pulse rate or heart rate, and it is not a paradoxical rise in systolic pressure. Normally, blood pressure drops less precipitously than 10 mmHg during inhalation. Pulsus paradoxus is a sign that is indicative of several conditions, most commonly pericardial effusion.

Tachycardia-induced cardiomyopathy (TIC) is a disease where prolonged tachycardia or arrhythmia causes an impairment of the myocardium, which can result in heart failure. People with TIC may have symptoms associated with heart failure and/or symptoms related to the tachycardia or arrhythmia. Though atrial fibrillation is the most common cause of TIC, several tachycardias and arrhythmias have been associated with the disease.

A plot of a system's pressure versus volume has long been used to measure the work done by the system and its efficiency. This analysis can be applied to heat engines and pumps, including the heart. A considerable amount of information on cardiac performance can be determined from the pressure vs. volume plot. A number of methods have been determined for measuring PV-loop values experimentally.

<span class="mw-page-title-main">Heart failure with preserved ejection fraction</span> Medical condition

Heart failure with preserved ejection fraction (HFpEF) is a form of heart failure in which the ejection fraction – the percentage of the volume of blood ejected from the left ventricle with each heartbeat divided by the volume of blood when the left ventricle is maximally filled – is normal, defined as greater than 50%; this may be measured by echocardiography or cardiac catheterization. Approximately half of people with heart failure have preserved ejection fraction, while the other half have a reduction in ejection fraction, called heart failure with reduced ejection fraction (HFrEF).

Tissue Doppler echocardiography (TDE) is a medical ultrasound technology, specifically a form of echocardiography that measures the velocity of the heart muscle (myocardium) through the phases of one or more heartbeats by the Doppler effect of the reflected ultrasound. The technique is the same as for flow Doppler echocardiography measuring flow velocities. Tissue signals, however, have higher amplitude and lower velocities, and the signals are extracted by using different filter and gain settings. The terms tissue Doppler imaging (TDI) and tissue velocity imaging (TVI) are usually synonymous with TDE because echocardiography is the main use of tissue Doppler.

In cardiology, ventricular dyssynchrony is a difference in the timing, or lack of synchrony, of contractions in different ventricles in the heart. Large differences in timing of contractions can reduce cardiac efficiency and is correlated with heart failure.

In clinical cardiology the term "diastolic function" is most commonly referred as how the heart fills. Parallel to "diastolic function", the term "systolic function" is usually referenced in terms of the left ventricular ejection fraction (LVEF), which is the ratio of stroke volume and end-diastolic volume. Due to the epidemic of heart failure, particularly the cases determined as diastolic heart failure, it is increasingly urgent and crucial to understand the meaning of “diastolic function”. Unlike "systolic function", which can be simply evaluated by LVEF, there are no established dimensionless parameters for "diastolic function" assessment. Hence to further study "diastolic function" the complicated and speculative physiology must be taken into consideration.

<span class="mw-page-title-main">Pathophysiology of heart failure</span>

The main pathophysiology of heart failure is a reduction in the efficiency of the heart muscle, through damage or overloading. As such, it can be caused by a wide number of conditions, including myocardial infarction, hypertension and cardiac amyloidosis. Over time these increases in workload will produce changes to the heart itself:

References

  1. ↑ Appleton CP, Galloway JM, Gonzalez MS, Gaballa M, Basnight MA (December 1993). "Estimation of left ventricular filling pressures using two-dimensional and Doppler echocardiography in adult patients with cardiac disease. Additional value of analyzing left atrial size, left atrial ejection fraction and the difference in duration of pulmonary venous and mitral flow velocity at atrial contraction". Journal of the American College of Cardiology. 22 (7): 1972–82. doi: 10.1016/0735-1097(93)90787-2 . PMID   8245357.
  2. 1 2 Sonnenblick EH (July 1968). "Correlation of myocardial ultrastructure and function". Circulation. 38 (1): 29–44. doi: 10.1161/01.cir.38.1.29 . PMID   11712290.
  3. ↑ Krishnamurthy GT, Bobba VR, Kingston E (March 1981). "Radionuclide ejection fraction: a technique for quantitative analysis of motor function of the human gallbladder". Gastroenterology. 80 (3): 482–90. doi:10.1016/0016-5085(81)90009-3. PMID   7450441.
  4. ↑ Christopoulos DG, Nicolaides AN, Szendro G, Irvine AT, Bull ML, Eastcott HH (January 1987). "Air-plethysmography and the effect of elastic compression on venous hemodynamics of the leg". Journal of Vascular Surgery. 5 (1): 148–59. doi: 10.1016/0741-5214(87)90205-9 . PMID   3795381.
  5. ↑ Cikes M, Solomon SD (June 2016). "Beyond ejection fraction: an integrative approach for assessment of cardiac structure and function in heart failure". European Heart Journal. 37 (21): 1642–50. doi: 10.1093/eurheartj/ehv510 . PMID   26417058.
  6. ↑ Ponikowski P, Voors AA, Anker SD, Bueno H, Cleland JG, Coats AJ, et al. (July 2016). "2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure: The Task Force for the diagnosis and treatment of acute and chronic heart failure of the European Society of Cardiology (ESC) Developed with the special contribution of the Heart Failure Association (HFA) of the ESC". European Heart Journal. 37 (27): 2129–2200. doi: 10.1093/eurheartj/ehw128 . PMID   27206819.
  7. ↑ Armstrong WF, Ryan T, Feigenbaum H (2010). Feigenbaum's Echocardiography. Lippincott Williams & Wilkins. ISBN   978-0-7817-9557-9.
  8. 1 2 3 4 Wood PW, Choy JB, Nanda NC, Becher H (2014). "Left ventricular ejection fraction and volumes: it depends on the imaging method". Echocardiography. 31 (1): 87–100. doi:10.1111/echo.12331. PMC   4231568 . PMID   24786629.
  9. 1 2 Asferg C, Usinger L, Kristensen TS, Abdulla J (May 2012). "Accuracy of multi-slice computed tomography for measurement of left ventricular ejection fraction compared with cardiac magnetic resonance imaging and two-dimensional transthoracic echocardiography: a systematic review and meta-analysis". European Journal of Radiology. 81 (5): e757-62. doi:10.1016/j.ejrad.2012.02.002. PMID   22381439.
  10. ↑ Motwani M, Berman DS, Germano G, Slomka P (February 2016). "Automated Quantitative Nuclear Cardiology Methods". Cardiology Clinics. 34 (1): 47–57. doi:10.1016/j.ccl.2015.08.003. PMC   4877137 . PMID   26590779.
  11. ↑ Van der Wall EE, Bax JJ (August 2000). "Different imaging approaches in the assessment of left ventricular dysfunction: all things equal?". European Heart Journal. 21 (16): 1295–7. doi: 10.1053/euhj.2000.2195 . PMID   10952821.
  12. ↑ Wackers FJ, Berger HJ, Johnstone DE, Goldman L, Reduto LA, Langou RA, Gottschalk A, Zaret BL (June 1979). "Multiple gated cardiac blood pool imaging for left ventricular ejection fraction: validation of the technique and assessment of variability". The American Journal of Cardiology. 43 (6): 1159–66. doi:10.1016/0002-9149(79)90148-6. PMID   443176.
  13. ↑ Marcu CB, Beek AM, van Rossum AC (October 2006). "Clinical applications of cardiovascular magnetic resonance imaging". Canadian Medical Association Journal. 175 (8): 911–7. doi:10.1503/cmaj.060566. PMC   1586078 . PMID   17030942.
  14. ↑ Kenny, JE (Dec 2018). "Systolic Time Intervals". Pulmccm.org.
  15. ↑ Kumar V, Abbas AK, Aster J (2009). Robbins and Cotran pathologic basis of disease (8th ed.). St. Louis, Mo: Elsevier Saunders. p. 574. ISBN   978-1-4160-3121-5.
  16. ↑ Mahadevan G, Davis RC, Frenneaux MP, Hobbs FD, Lip GY, Sanderson JE, Davies MK (April 2008). "Left ventricular ejection fraction: are the revised cut-off points for defining systolic dysfunction sufficiently evidence based?". Heart. 94 (4): 426–8. doi:10.1136/hrt.2007.123877. PMID   18347374. S2CID   45337388.
  17. 1 2 3 4 5 6 7 Maceira AM, Prasad SK, Khan M, Pennell DJ (December 2006). "Reference right ventricular systolic and diastolic function normalized to age, gender and body surface area from steady-state free precession cardiovascular magnetic resonance" (PDF). European Heart Journal. 27 (23): 2879–88. doi:10.1093/eurheartj/ehl336. PMID   17088316.
  18. 1 2 3 4 5 6 7 Maceira A (2006). "Normalized Left Ventricular Systolic and Diastolic Function by Steady State Free Precession Cardiovascular Magnetic Resonance". Journal of Cardiovascular Magnetic Resonance. 8: 417–426. doi:10.1080/10976640600572889.(subscription required)
  19. 1 2 Normal ranges for heart rate are among the narrowest limits between bradycardia and tachycardia. See the Bradycardia and Tachycardia articles for more detailed limits.
  20. 1 2 "Normal Hemodynamic Parameters – Adult" (PDF). Edwards Lifesciences LLC. 2009.
  21. ↑ McDonagh, Theresa A; Metra, Marco; Adamo, Marianna; Gardner, Roy S; Baumbach, Andreas; Böhm, Michael; Burri, Haran; Butler, Javed; Čelutkienė, Jelena; Chioncel, Ovidiu; Cleland, John G F; Coats, Andrew J S; Crespo-Leiro, Maria G; Farmakis, Dimitrios; Gilard, Martine (2021-09-21). "2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure". European Heart Journal. 42 (36): 3599–3726. doi: 10.1093/eurheartj/ehab368 . ISSN   0195-668X. PMID   34447992.
  22. ↑ "4.00-Cardiovascular-Adult".
  23. ↑ Armstrong WF, Ryan T (2012-02-03). Feigenbaum's Echocardiography. Lippincott Williams & Wilkins. p. 126. ISBN   9781451147834.
  24. ↑ Bruce TA, Chapman CB (November 1965). "Left ventricular residual volume in the intact and denervated dog heart". Circulation Research. 17 (5): 379–85. doi: 10.1161/01.res.17.5.379 . PMID   5843876.
  25. ↑ Chauveau JB, Faivre J (1856). "Nouvelles recherches expérimentales sur les mouveménts et les bruits normaux du coeur envisages au point de vue la physiologie medicale". Caz. Med. De Par. 365: 406.
  26. ↑ Adami JG (December 1888). "Remarks on Failure of the Heart from Overstrain". British Medical Journal. 2 (1459): 1321–6. doi:10.1136/bmj.2.1459.1321. PMC   2198364 . PMID   20752520.
  27. ↑ Henderson Y (1906). "The volume curve of the ventricles of the mammalian heart, and the significance of this curve in respect to the mechanics of the heart-beat and the filling of the ventricles". Am J Physiol. 16 (3): 325–67. doi:10.1152/ajplegacy.1906.16.3.325.
  28. ↑ Nylin G (1933). "The relation between heart volume and cardiac output per beat as a measure of cardiac activity". Svenska Läkartidningen. 10: 1.
  29. ↑ Bing RJ, Heimbecker R, Falholt W (October 1951). "An estimation of the residual volume of blood in the right ventricle of normal and diseased human hearts in vivo". American Heart Journal. 42 (4): 483–502. doi:10.1016/0002-8703(51)90146-9. PMID   14877744.
  30. ↑ Holt JP (March 1956). "Estimation of the residual volume of the ventricle of the dog's heart by two indicator dilution technics". Circulation Research. 4 (2): 187–95. doi: 10.1161/01.res.4.2.187 . PMID   13293819.
  31. ↑ Folse R, Braunwald E (April 1962). "Determination of fraction of left ventricular volume ejected per beat and of ventricular end-diastolic and residual volumes. Experimental and clinical observations with a precordial dilution technic". Circulation. 25: 674–85. doi: 10.1161/01.cir.25.4.674 . PMID   13893859.
  32. ↑ Elliott, William C.; Lane, Francis J.; Gorlin, Richard (January 1964). "Measurement of left ventricular volume in man by thermodilution". The American Journal of Cardiology. 13 (1): 106. doi:10.1016/0002-9149(64)90274-7.
  33. ↑ Bartle SH, Sanmarco ME, Dammann J (1965). "5. Ejected fraction: An index of myocardial function". The American Journal of Cardiology. 15 (1): 125. doi:10.1016/0002-9149(65)90615-6.
  34. ↑ Krayenbühl HP, Bussmann WD, Turina M, Lüthy E (1968). "Is the ejection fraction an index of myocardial contractility?". Cardiologia. 53 (1): 1–10. doi:10.1159/000166167. PMID   5733881.
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