You can assess the LV systolic function by POCUS by just zeroing in on the following cardiac parameters: 1. Anterior mitral valve leaflet motion in early diastole; 2. Change in LV chamber diameter; and 3. LV wall thickness during systole.1
First assess the anterior mitral valve leaflet motion towards the interventricular septum in early diastole in the parasternal long axis view (Figure). Estimated or measured distance between anterior mitral valve leaflet and the interventricular septum is called E-point septal separation (EPSS). When LV systolic function is normal, anterior mitral valve leaflet opens fully in early diastole, resulting in a small or minimal separation between it and the interventricular septum. Due to the fixed length of the chordae and the enlarged LV chamber size, anterior mitral valve leaflets are unable to fully open as systolic function worsens. This results in increased separation between the anterior mitral valve leaflet and the interventricular septum. An estimated EPSS greater than 10 mm is considered abnormal and suggests LV dysfunction.1,2
You can also estimate the LV ejection fraction (LVEF) quantitatively by utilizing the following formula:3
LVEF (%)=75.5 – 2.5xEPSS (mm)
Keep in mind that aortic insufficiency and mitral stenosis can affect the accuracy of this formula.1
As for assessing the LV chamber diameter and wall thickness, recall that these parameters are also dynamic throughout the cardiac cycle. In systole, LV diameter should decrease by 30-40% while LV wall thickness should increase by approximately 40%. Using this as a guide, you can perform qualitative assessment by “eyeballing” the LV systolic function in parasternal long axis, parasternal short axis, apical 4-chamber and subcostal 4-chamber views. Beware that in parasternal long axis, apical 4-chamber and subcostal 4-chamber views, off axis of images can foreshorten the chamber size, resulting in overestimation of systolic function. Also be sure to use the midventricular papillary muscle view when assessing systolic function in the parasternal short axis.1
Once you have obtained all the necessary images, feel free to categorize the systolic function as either “hyperdynamic”, “normal”, “reduced” or “severely reduced” (watch video below).1
Bonus pearl: Did you know that qualitative assessment of the LV systolic function following brief training sessions have been shown to significantly correlate with that obtained by formal echocardiography (k = 0.77, p <0.001).1,4,5
Contributed by Woo Moon, D.O, Director POCUS Training Program, Mercy-St. Louis Hospital, St. Louis, Missouri
Figure: EPSS in normal vs reduced EF
Note: EPSS (yellow arrows) is narrow in normal but wide in reduced EF
Video: Four categories of systolic function
References
- Soni MD MS NJ, Arntfield MD FRCPC R, Kory MD MPA P. Point of Care Ultrasound. 2nd ed. St. Louis, MO: Elsevier; 2019. . https://www.elsevier.com/books/point-of-care-ultrasound/soni/978-0-323-54470-2
- Kimura BJ, Yogo N, O’Connell CW, Phan JN, Showalter BK, Wolfson T. Cardiopulmonary limited ultrasound examination for “quick-look” bedside application. Am J Cardiol 2011;108(4):586–90. https://linkinghub.elsevier.com/retrieve/pii/S0002-9149(11)01424-X
- Silverstein JR, Laffely NH, Rifkin RD. Quantitative estimation of left ventricular ejection fraction from mitral valve E-point to septal separation and comparison to magnetic resonance imaging. Am J Cardiol 2006;97(1):137–40. https://www.ajconline.org/article/S0002-9149(05)01683-8/fulltext
- Melamed R, Sprenkle MD, Ulstad VK, Herzog CA, Leatherman JW. Assessment of left ventricular function by intensivists using hand-held echocardiography. Chest 2009;135(6):1416–20. https://journal.chestnet.org/article/S0012-3692(09)60341-X/fulltext
- Johnson BK, Tierney DM, Rosborough TK, Harris KM, Newell MC. Internal medicine point-of-care ultrasound assessment of left ventricular function correlates with formal echocardiography. J Clin Ultrasound 2016;44(2):92–9. https://onlinelibrary.wiley.com/doi/10.1002/jcu.22272
