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THE LEFT VENTRICLE
Most ED assessment of cardiac structure and function is done qualitatively. However, to do this, you need an idea of what the normal measurements are. The following section will go through the basic measurements for the left ventricle. Most of these are done in the PLAx and PSAx
PLAx is usually the window for most of the LV measurements. If doing measurements, the current recommendation is to freeze the clip at end diastole and measure in 2D rather than using m mode (1). If you don't have ECG leads: end diastole is the frame before mitral valve closure and end systole is the frame in which the aortic valve closes (2).
Measurements should be made at the level of the mitral valve leaflet tips. The axis of measurement should be perpendicular to the long axis of the LV.
LV wall thickness and cavity measurement in 2D
You can also do the measurements with M mode. In this case, make sure the M mode cursor is perpendicular to the long axis of the LV. You may need to be a bit off axis (ie heart on its head) to achieve this.
LV wall thickness and cavity measurement on M mode
LVIDd = LV end diastolic diameter
LVIDs = LV end systolic diameter
IVSd = Interventricular septum diameter
LVPWd = LV inferolateral wall diameter
from BSE 2020 (2)
LVIDd<6cm LV wall thickness <10mm
LV SYSTOLIC FUNCTION
EYEBALL METHOD
One of the best methods to determine decreased systolic function at the bedside is the eyeball method (3). This method is highly accurate and correlates well with more technical means of measuring LVEF such as Simpsons method (4). To become an expert at this, you need to look at a lot of normal and abnormal. Unluer et al (5) showed that EPs assessment of EF had a high level of correlation with cardiologists' interpretation after a 2 hour didactic session on bedside echo and 60 cases of EF estimation with an echocardiographer . Akinboboye et al (6) showed there was a significant improvement in accuracy when participants reviewed 20 cases and were given immediate feedback on the EF estimation . If you can, go into your cardiology echo archives, look at the scans and then match your assessment with the report. The more you see, the more confident you will be with normal and abnormal.
The LV cavity should change 30-50% between diastole and systole with the LV walls moving symmetrically into the centre. When the LV cavity is obliterated and the papillary muscles meet (kissing pap muscles) with each systolic contraction, the LV function is termed hyperdynamic. A hyperdynamic LV suggests an LVEF >75% (Range of LVEF shown below). A severely impaired LV will have minimal change to cavity diameter.
LV systolic function is best assessed in PLAx and PSAx.
Examples of LVEF PLAx
top row from left to right: hyperdynamic (>75%), normal (>55%), mildly impaired (40-50%), bottom row left to right : moderately impaired (30-40%) and severely impaired (<30%)
Examples of LV EF PSAx
top row from left to right: hyperdynamic (>75%), normal (>55%), mildly impaired (40-50%),
bottom row left to right : moderate (30-40%), moderate to severe (30%) severely impaired (10-20%)
EPSS
Another assessment of LV systolic function is the excursion of the anterior mitral leaflet in diastole: E point septal separation (EPSS). When LV systolic function is normal, the anterior mitral leaflet should approach within 5mm of the interventricular septum (7). EPSS >10mm closely correlates with reduced EF (8)
EPSS measurement in 2D
The EPSS can be estimated qualitatively on the moving image, or quantitatively by measuring in 2D or with M mode.
Schematic of M mode of Mitral valve in M mode
Normal EPSS <5mm
Increased EPSS
Normal EPSS <5mm
The mitral valve flickers twice during diastole. The first is due to passive filling due to the pressure differential (E wave) and the second is due to atrial contraction (A wave). Measure the distance with the first flicker. In 2D, this is easiest in PLAx.
For M mode PLAx or PSAx can be used. There will be two waves in the LV cavity. Measure the distance from the peak of the first wave to the IV septum. Ensure the M mode line is perpendicular to the axis of the heart otherwise you will over estimate the EPSS.
The caveat to this is mitral valve disease such as rheumatic disease or calcification which prevent the mitral valve from opening fully.
FRACTIONAL SHORTENING
This is an extrapolation of EF based on the 2D measurements of the LV cavity length in diastole (LVIDd) and systole (LVIDs). It is a 2D measurement on a single line of sight. It is not very accurate in the presence of regional wall motional abnormalities and is tedious to do.
VTI
VTI (Velocity Time Integral) is performed with the pw doppler gate at the LVOT. It is a measure of the distance traveled by blood during systole over time. It has been shown to correlate well with quantitative EF measurements (9,10) and can be used to determine fluid responsiveness and response to inotropes.
Normal LVOT VTI is 18-22cm
Reduced LVOT VTI <18cm
Hyperdynamic LVOT VTI >22
VTI: normal 18-22, Reduced <18, hyperdynamic >22
LV WALLS and ARTERIAL TERRITORIES
The normal LV myocardium should increase in thickness by 50% with each systole. In acute ischaemia, the myocardium won't thicken with systole but will have a normal thickness in diastole. With infarction and scar formation, the myocardium becomes thin (<6mm) and doesn't thicken with systole. Aneurysm formation usually causes the myocardium to have a paradoxical movement in systole.
The easiest view to assess for regional wall motion abnormality (RWMA) is PSAx at the level of the pap muscles. Concentrate on the central anechoic cavity and get a feel for which walls are coming in to the centre and which ones remain immobile.
A simplified version of the arterial supply of the LV:
PLAx: IV septum and inferolateral wall.
When the aorta is visible as in PLAx, the anterior part of the IV septum is visualised. This is supplied by the left anterior descending artery (LAD).
The inferolateral wall is supplied by the right coronary artery (RCA), the L circumflex (LCx) or a combination of both.
PSAx
All the walls of the LV are seen in this view. The anterior half of the interventricular septum and the anterior wall is supplied by the LAD. The lateral wall is supplied by the L circumflex artery. The inferior half of the interventricular septum and the inferolateral wall are supplied by the RCA
A4C
The interventicular septum in this view is the inferior part of the septum (aorta not in view) and so is supplied by the RCA. The inferolateral wall is supplied by the L circumflex (or LAD).
A2C
The reason people do this view is because it gives the true anterior (LAD) and true inferior (RCA) views of the LV. In this was it is possible to isolate the arterial territories. The anterior wall is supplied by the LAD and the inferior wall is supplied by the RCA.
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REFERENCES
1. 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
2. Harkness A, Ring L, Augustine DX, et al. Normal reference intervals for cardiac dimensions and function for use in echocardiographic practice: a guideline from the British Society of Echocardiography [published correction appears in Echo Res Pract. 2020 Mar 20;7(1):X1]. Echo Res Pract. 2020;7(1):G1-G18. Published 2020 Feb 24. doi:10.1530/ERP-19-0050
3. Bahl A, Johnson S, Altwail M, Brackney A, Xiao J, Price J, Shotkin P, Chen NW. Left Ventricular Ejection Fraction Assessment by Emergency Physician-Performed Bedside Echocardiography: A Prospective Comparative Evaluation of Multiple Modalities. J Emerg Med. 2021 Dec;61(6):711-719
4. Gudmundsson P, Rydberg E, Winter R, Willenheimer R. Visually estimated left ventricular ejection fraction by echocardiography is closely correlated with formal quantitative methods. Int J Cardiol. 2005 May 25;101(2):209-12. doi: 10.1016/j.ijcard.2004.03.027. PMID: 15882665.
5. Unlüer EE, Karagöz A, Akoğlu H, Bayata S. Visual estimation of bedside echocardiographic ejection fraction by emergency physicians. West J Emerg Med. 2014 Mar;15(2):221-6.
6. Akinboboye O, Sumner J, Gopal A, King D, Shen Z, Bardfeld P, Blanz L, Brown EJ Jr. Visual estimation of ejection fraction by two-dimensional echocardiography: the learning curve. Clin Cardiol. 1995 Dec;18(12):726-9.
7. Ginzton LE, Kulick D. Mitral valve E-point septal separation as an indicator of ejection fraction in patients with reversed septal motion. Chest. 1985;88(3):429-31.
8. Núñez-Ramos JA, Pana-Toloza MC, Palacio-Held SC. E-Point Septal Separation Accuracy for the Diagnosis of Mild and Severe Reduced Ejection Fraction in Emergency Department Patients. POCUS J. 2022 Apr 21;7(1):160-165.
9. Blanco P. Rationale for using the velocity-time integral and the minute distance for assessing the stroke volume and cardiac output in point-of-care settings. Ultrasound J. 2020 Apr 21;12(1):21.
10. Spathoulas K, Tsolaki V, Zakynthinos GE, Karelas D, Makris D, Zakynthinos E, Papanikolaou J. The Role of Left Ventricular Ejection Fraction and Left Ventricular Outflow Tract Velocity-Time Integral in Assessing Cardiovascular Impairment in Septic Shock. J Pers Med. 2022 Oct 29;12(11):1786.
11. Goldman JH, Schiller NB, Lim DC, Redberg RF, Foster E (2001) Usefulness of stroke distance by echocardiography as a surrogate marker of cardiac output that is independent of gender and size in a normal population. Am J Cardiol 87:499–502