Cardiac Ultrasound Q&A

1.) What is indicated by the labels X and Y?

  • X = The mitral waveform e-point. This represents the first opening of the mitral valve during diastole.
  • Y = The mitral waveform a-point represents mitral leaflet movement associated with atrial contraction.

2.) What is being measured here?

E-point septal separation (EPSS). It is a rough measure of left ventricular ejection fraction. It is measured using m-mode and is the minimal distance between the anterior leaflet of the mitral valve and parasternal long view during mitral valve opening (or diastole). the distance between the interventricular septum and the e-point of the mitral valve.


3.) What conditions make this measurement inaccurate?

Mitral valve disease that restricts mitral leaflet motion, hypertrophy of the left ventricular wall, localized septal wall motion abnormalities can make the measurement inaccurate. Failure to obtain a true parasternal long-axis view.


4.) Is this method accurate?

Increased EPSS correlates strongly with a low ejection fraction and can be accurately performed by emergency medicine residents.(1,2) The sensitivity of an EPSS measurement of greater than 7 mm for severe systolic dysfunction (LVEF≤30%) is 100.0% (62.9-100.0) with a specificity of 51.6% (38.6-64.5). (1) A measurement greater than 7mm correlates with an EF <30%.(1) data-preserve-html-node="true" When compared to fractional shortening, EPSS did not perform as favorably, but when compared to cardiac MRI LVEF and MRI measurements of EPSS, the correlation was very strong.(3,4) Likely, much of the error associated with measurements is due to poor windows or inaccurate angles.

5.) What is the ejection fraction based on this study? Good, poor, or severely decreased?

The measurement is 3.08 cm, which is 30.8mm. EPSS greater than 7mm correlates with an EF <30% data-preserve-html-node="true" so we know the EF is less than 30%. In this case, the EF is severely decreased.


  1. McKaigney CJ, Krantz MJ, La Rocque CL, Hurst ND, Buchanan MS, Kendall JL. E-point septal separation: a bedside tool for emergency physician assessment of left ventricular ejection fraction.  Am J Emerg Med. 2014 Jun;32(6):493-7.

  2. Secko MA, Lazar JM, Salciccioli LA, Stone MB. Can junior emergency physicians use E-point septal separation to accurately estimate left ventricular function in acutely dyspneic patients? Acad Emerg Med. 2011 Nov; 18(11):1223-6.

  3. Weekes AJ, Reddy A, Lewis MR, Norton HJ. E-point septal seapartion compared to fractional shortening measurements of systolic function in emergency department patients: prospective randomized study. J Ultrasound Med. 2012 Dec;31(12):1891

  4. Elagha A and Fuisz A. Mitral valve E-point to septal separation (EPSS) measurement by cardiac magnetic resonance Imaging as a quantitative surrogate of Left Ventricular Ejection Fraction (LVEF). J cardiovasc Magn Reson. 2012; 14 (Suppl 1): P154