Left ventricular function assessment
Etiology
Etiology of left ventricular (LV) dysfunction can be of various origin (Image 1+2)
Normal values of left ventricle (Images 3-6)
Adapted from: Lang RM, et al. Recommendations for Cardiac Chamber Quantification by Echocardiography in Adults: An Update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. Eur Heart J Cardiovasc Imaging. 2016 Apr;17(4):412. doi: 10.1093/ehjci/jew041. Epub 2016 Mar 15. Erratum for: Eur Heart J Cardiovasc Imaging. 2015 Mar;16(3):233-70.
Adapted from: Lang RM, et al. Recommendations for Cardiac Chamber Quantification by Echocardiography in Adults: An Update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. Eur Heart J Cardiovasc Imaging. 2016 Apr;17(4):412. doi: 10.1093/ehjci/jew041. Epub 2016 Mar 15. Erratum for: Eur Heart J Cardiovasc Imaging. 2015 Mar;16(3):233-70.
Adapted from: McDonagh TA, Metra M, Adamo M, et al. ESC Scientific Document Group. 2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure. Eur Heart J. 2021 Sep 21;42(36):3599-3726. doi: 10.1093/eurheartj/ehab368. PMID: 34447992.
Adapted from: Lang RM, et al. Recommendations for Cardiac Chamber Quantification by Echocardiography in Adults: An Update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. Eur Heart J Cardiovasc Imaging. 2016 Apr;17(4):412. doi: 10.1093/ehjci/jew041. Epub 2016 Mar 15. Erratum for: Eur Heart J Cardiovasc Imaging. 2015 Mar;16(3):233-70.
Left ventricular systolic function examination methods
LV global systolic function is generally assessed by measuring the difference between the end-diastolic and end-systolic value divided by the end-diastolic value. This can be applied for either a one-dimensional 2D or in 3D image.
There are numerous ways to quantify and measure left ventricular function.
1. Eyeballing method
This method is based on visual assessment of left ventricular function. The examiner observes myocardial wall thickening and the motion of endocardium. According to that the physician is able to evaluate the regional myocardial function.
We observe regional deformation of myocardium such as thickening and shortening or displacement (Image 7). These regional deformation and wall motion abnormalities often correlate with reduced LVF.
The American Society of Echocardiography recommends the use of a 17-segment model (Image 8).
Each segment is visually assessed for wall motion and myocardial contractility abnormalities which allows to estimate LVF visually.
Image 7 Wall motion abnormaties
Image 8 The recommended definition of LV division of 17 segments on echocardiographic views
Coulter S.A. (2015) Echocardiographic Evaluation of Coronary Artery Disease. In: Willerson J., Holmes, Jr. D. (eds) Coronary Artery Disease. Cardiovascular Medicine. Springer, London. https://doi.org/10.1007/978-1-4471-2828-1_10
2. Fractional shortening
When using this method there are two important parameters which are measured using the M-mode. These parameters are left ventricular end-systolic diameter (LVESD) and the left ventricular end-diastolic diameter (LVEDD). The parameters illustrate the size of the left ventricle in the end-systolic and end-diastolic phase of the cardiac cycle (Image 9).
Formula: (LVEDD - LVESD / LVEDD) x 100
By using the formula above we can calculate the percentage of size differences of the left ventricle and then use this to determine how sufficiently the left ventricle is contracting and therefore shrinks its size during systole.
Values > 25% are considered to be normal in M-mode.
Volume measurements based on linear measurements are nowadays thought to be inexact and according to latest guidelines they should not be used anymore to determine LV function as well as the Teichholz formula where the ventricular diameter D is measured during M-Mode.
Image 9 Fractional shortening overview
From: Fractional shortening for estimation of ejection fraction. (n.d.). [Illustration]. Ecgwaves.Com. https://ecgwaves.com/topic/fractional-shortening-for-estimation-of-ejection-fraction/
Image 10 Fractional shortening (PLAX view)
3. Ejection fraction
Ejection fraction is a parameter which is calculated from the End Diastolic Volume and End Systolic Volume estimated sizes.
Currently the Simpson method, a biplane method, derived from a 2D or 3D images is recommended to assess the LV EF.
Formula: EF = (EDV-ESV)/EDV x 100
(EF= Ejection fraction, EDV= End-Diastolic Volume, ESV= End-Systolic Volume)
Generally LV Ejection Fraction should be 52-72% in men and 54-74% in women. The abnormal values of LV ejection fraction are further divided according to its severity. The cut off values are listed in the following table (Image 16).
Image 11 Ejection fraction assessment by Simpsons method
Image 12 Evaluation of ejection fraction of the left ventricle biplane (A4C on the picture), Simpson’s method
Image 13 Evaluation of ejection fraction of the left ventricle from A2C projection, Simpson’s method
4. Cardiac output/index/Stroke volume
Doppler Echocardiography as well as 2D derived images are also used to determine cardiac functional and structural parameters.
Stroke volume, cardiac output and cardiac index are used.
The examiner can derive them from two measurements: The velocity time integral (VTI) and the cross-section of the Left ventricular outflow tract (LVOT).
The VTI shows the flow across the area of interest in this case the total volume flow during the systole. This method cannot be applied in patientss with a LVOT obstruction !
Cardiac output formula: CO= HR x (LVOT AREA x LVOT VTI)
Cardiac index formula: CI= CO/ BSA
Stroke volume formula: SV= LVOT AREA x LVOT VTI
Normal stroke volume = 70-110 ml (in exercise 80-130 ml)
Image 14 How to measure cardiac output
5. Global longitudinal strain rate
Global longitudinal strain (GLS) is a parameter representing the changes in the size of the left ventricle in a particular direction relative to LV baseline length.
This method allows us to evaluate regional myocardial function and it directly shows the ability of myocardial regions to contract.
It serves as a sensitive and early predictor of regional LV function impairment even before Ejection fraction is decreased.
GLS measures the shortening of the myocardium and the shortening correlates with myocardial contractility.
The strain rate is measured by dividing the change of systolic and diastolic velocities by the distance of measured points. The Strain rate is then calculated using the formula below.
Formula: GLS (%) = (MLs-MLd)/MLd
(MLs = Myocardial length during systole, MLd = myocardial length during diastole)
The result is presented as a percentage of change in myocardial length.
GLS percentage values are negative because the length of myocardium during systole is smaller than during diastole. Because of that it means that when the GLS values are negative it should be interpreted as myocardial contraction and vice versa when the values are positive the myocardium is relaxing.
Image 15 Factors affecting strain values
Voigt JU, Cvijic M. 2- and 3-Dimensional Myocardial Strain in Cardiac Health and Disease. JACC Cardiovasc Imaging. 2019 Sep;12(9):1849-1863. doi: 10.1016/j.jcmg.2019.01.044. PMID: 31488253.
Image 16 Grading of LV strain
Adapted from: Vijayaraghavan, Govindan & Sivasubramonian, Sivasankaran. (2020). Global Longitudinal Strain: A practical Step-by-Step Approach to Longitudinal Strain Imaging. Journal of The Indian Academy of Echocardiography & Cardiovascular Imaging. 4. 22. 10.4103/jiae.jiae_16_19.
6. Strain and Strain rate assessed by speckle tracking
Another method is Strain and Strain rate assessed by speckle tracking. The examiner uses 2D mode to perform speckle tracking myocardial velocities and various parameters of myocardial deformation which enables calculation of strain and strain rate.
It works by measuring different components of myocardial contraction and it then delivers information on global contraction assessing the longitudinal strain, but also the circumferential and radial strain during cardiac cycle. The results of measurements can then be visualised in different ways.
One way of visualisation is called a “bulls eye” display, the other one shows curves according to the change in strain over time in M-mode.
An advantage of the speckle tracking method is that it isn’t dependent on the angle of visualisation. Strain rate is nowadays used to assess and calculate regional myocardial function as it provides exact information about cardiac wall movement. Strain rate assessed by speckle tracking should be performed using the same equipment and software because of software variability between ultrasound devices.
Image 17 Speckle tracking
From:ECG & Echo Waves. (2020, September 23). Strain, strain rate and speckle tracking: Myocardial deformation –. ECG & ECHO. https://ecgwaves.com/topic/deformation-strain-strain-rate-speckle-tracking-echocardiography/
Normal values of lower limits of normal range with Doppler:
Longitudinal strain - 18,5% and 1.00 sec^-1
Radial strain - 44,5% and 2.45 sec ^-1
7. Contractility (dp/dt)
Dp/dt is a parameter which evaluates the ability of myocardium to contract. This method works by measuring the rate of pressure increase during the systole.
The basic principle is that the faster myocardium contracts the faster the pressure in the ventricle builds up and the better the function of the left ventricle is.
The pressure increment is evaluated by the mitral regurgitation profile using visualization CW Doppler over the mitral valve.
The speed of pressure build up is measured at two different time points: 1m/s and 3 m/s.
Then the examiner calculates the difference between the two timepoints and the result represents the time needed for a 32 mmHg change of intraventricular pressure within the left ventricle.
When using this method we must keep in mind that in several pathologies such as LBBB, RV pacing and WPW syndrome dp/dt may be reduced due to dyssynchrony and not because of reduced contractility. The formula used to calculate cardiac contractility is:
Formula: dp/dt = 32 mmHg/ time (seconds) or 32mmHg x 1000/ time (milliseconds)
Image 18 dp/dt measurement
Image 19 dp/dt reference values
8. Myocardial performance index (Tei index)
Myocardial performance index (MPI) is a parameter for global ventricular performance.
Time intervals by tissue Doppler imaging derived from septal annulus.
The MPI consists of 3 variables which are derived from Doppler spectrum- ICT, IRT, ET (ET – ejection time, ICT- isovolumic contraction time, IRT- isovolumic relaxation time).
When systolic dysfunction is present ICT will increase and ET decrease. Such condition leads to an increased MPI.
Formula: MPI = (ICT + IRT) / ET
Normal range is considered at 0,39+/-0,05.
An MPI over 0,5 is considered abnormal.
Image 20 How to measure Myocardial performance index
Ulucam M, Yildirir A, Muderrisoglu H, et al. Effects of hemodialysis on myocardial performance index. Adv Ther. 2004 Mar-Apr;21(2):96-106. doi: 10.1007/BF02850337. PMID: 15310083.
Image 21 Myocardial performance index
Alsafi Z, Malmgren A, Gudmundsson P, Stagmo M, Dencker M. Myocardial performance index in female athletes. Cardiovasc Ultrasound. 2017 Sep 11;15(1):20. doi: 10.1186/s12947-017-0112-9. PMID: 28893266; PMCID: PMC5594499.
9. MAPSE - Mitral Annular Plane Systolic Excursion
Another approach to quantify LVF. It is an M-Mode derived marker of longitudinal Left ventricular function.
For the calculation the M-Mode is placed in an apical four-chamber view on the lateral mitral annulus, measuring the excursion of mitral valve during systole and diastole.
A MAPSE > 1 cm is considered normal.
Image 22 MAPSE measurement
Terada T, Mori K, Inoue M, Yasunobu H. Mitral annular plane systolic excursion/left ventricular length (MAPSE/L) as a simple index for assessing left ventricular longitudinal function in children. Echocardiography. 2016 Nov;33(11):1703-1709. doi: 10.1111/echo.13325. Epub 2016 Aug 22. PMID: 27545275.
10. 3D Echocardiography
Rapid technological developments during the last years have led to newer techniques.
Disadvantages of 3D Echocardiography are the dependence on image quality, there are no standard normal values also because normal range cut-off values for 3D LVF EF vary among ethnic populations. Therefore 3D assessment of LVF should only be performed in laboratories with experience in 3D echocardiography.
ECHO library
1) a) Normal systolic function of the left ventricle
Video 1 Normal systolic function of the left ventricle, normal wall motion - PLAX
Video 2 Normal systolic function of the left ventricle, normal wall motion - PSAX
Video Normal systolic function of the left ventricle, normal wall motion - A4C
Video 3 Normal systolic function of the left ventricle, normal wall motion - A2C
Video 4 Normal systolic function of the left ventricle, normal wall motion - A3C
1 b) Severe systolic dysfunction of the left ventricle, diffuse hypokinesis
Video 5 Severe systolic dysfunction of the left ventricle, diffuse hypokinesis - PLAX
Video 6 Severe systolic dysfunction of the left ventricle, diffuse hypokinesis - PSAX
Video 7 Severe systolic dysfunction of the left ventricle, diffuse hypokinesis - A4C
Video 8 Severe systolic dysfunction of the left ventricle, diffuse hypokinesis - A2C
Video 9 Severe systolic dysfunction of the left ventricle, diffuse hypokinesis - A3C
2 a) Normal global longitudinal strain
Video 10 A3C image used for GLS measurement
Video 11 A4C image used for GLS measurement
Video 12 A2C image used for GLS measurement
Image 23 Normal global longitudinal strain
Image 24 Normal global longitudinal strain
2 b) Abnormal global longitudinal strain in patient with severe systolic dysfunction due to dilated cardiomyopathy
Image 25 Abnormal global longitudinal strain
Image 26 Abnormal global longitudinal strain
3. Ejection fraction evaluation by Simpson’s method
Image 27 Evaluation of ejection fraction of the left ventricle from A2C projection, Simpson’s method
Image 28 Evaluation of ejection fraction of the left ventricle biplane (A4C on the picture), Simpson’s method
3. Cardiac output measurement
Image 29 LVOT measurement - PLAX
Image 30 LVOT VTI measurement - A5C
4. Regional wall motion abnormalities
a) Akinesis
Video 13 Anterior myocardial infarction - akines of the apical 3/4 of the anteroseptum (occlusion of medial segment of left anterior descending artery) - PLAX
Video 14 Anterior myocardial infarction - severe hypokines/akinesis of the anterior and septal wall of the VV (occlusion of a medial segment of the left anterior descending artery) - PSAX view
Video 15 Anterior myocardial infarction - acute phase, akinesis of apex and apical 3/4 of inferoseptum, EF LV 35-40% (culprit lesion: occlusion of medial segment of left anterior descending artery) - A4C
Video 16 Anterior myocardial infarction - akinesis of apex and majortiy of anteroseptal wall, EF LV 35-40% (culprit lesion: occlusion of medial segment of left anterior descending artery) - A3C
Video 17 Anterior myocardial infarction - severe hypokinesis of anterior and septal wall - EF LV 30-35% - PSAX (midventricular)
Video 18 Anterior myocardial infarction - akinesis of apex and whole inferoseptal wall, hypercontracility of lateral wall - EF LV 30-35% - A4C
Video 19 Inferior myocardial infarction - severe hypokinesis/akinesis of basal 1/2 of inferior wall (culprit lesion: occlusion of distal segment of right coronary artery) - A2C
b) Hypokinesis
Video 20 Inferolateral myocardial infarction - hypokinesis of inferolateral wall (culprit lesion: occlusion of proximal segmentof circumflex artery) - PLAX
Video 21 Hypokinesis of inferior, inferolateral and inferosepta wall, EF LV 40-45% (occlusion of proximal segment of proximal segment of circumflex artery) - PSAX
Video 22 Inferolateral myocardial infarction - severe hypokinesis of inferolateral wall - A3C
Video 23 Inferior myocardial infarction - hypokinesis of inferior (culprit lesion: 70% stenosis of distal segment of right coronary artery) - PSAX
Video 24 Hypokinesis of basal ⅔ of lateral wall and inferoseptum - A4C
c) LV Aneurysm
Video 25 Anterior myocardial infarction - apical aneurysm and akinesis of apical ⅔ septal wall, hyperkinesis of inferolateral wall. Patient presented with cardiogenic shock, anterior STEMI on ECG, coronarography revealed multi vessel disease, culprit lesion: occlusion of left anterior descending artery - PLAX
Video 26 Apical aneurysm - A2C
Video 27 Thrombus an apical aneurysm - A4C
References
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5. Voigt JU, Cvijic M. 2- and 3-Dimensional Myocardial Strain in Cardiac Health and Disease. JACC Cardiovasc Imaging. 2019 Sep;12(9):1849-1863. doi: 10.1016/j.jcmg.2019.01.044. PMID: 31488253.
6. Vijayaraghavan, G. (2020, January 1). Global Longitudinal Strain: A practical Step-by-Step Approach to Longitudinal Strain Imaging Vijayaraghavan G, Sivasankaran S - J Indian Acad Echocardiogr Cardiovasc Imaging .Jiaecho.Org. https://www.jiaecho.org/article.asp?issn=2543-1463;year=2020;volume=4;issue=1;spage=22;epage=28;aulast=Vijayaraghavan
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8. Dinh, V. (n.d.). Measuring Cardiac Output with Echocardiography Made Easy. POCUS 101. Retrieved October 1, 2021, from https://www.pocus101.com/measuring-cardiac-output-with-echocardiography-made-easy/
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Various cardiac and extracardiac diseases can lead to systolic dysfunction of the left and right ventricle (Image 1+2).
