Madtown Sono

Elderly male with dyspnea

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By Michael Fareri, MD
Edited by Hani I. Kuttab, MD

Clinical Case

An elderly male with a history of congestive heart failure, coronary artery disease and hypertension presented to the emergency department with chest pain and shortness of breath for several days. He had a pacemaker placed approximately one month prior during a hospitalization for complete heart block. Lab workup is unremarkable, including serial troponins. Chest radiography is normal, and the electrocardiogram shows a ventricularly paced rhythm. To further evaluate for cardiac dysfunction, point of care ultrasound is performed (Figures 1 and 2).

Point-of-care cardiac ultrasound (parasternal long)
Figure 1. Point-of-care cardiac ultrasound (parasternal long)

Point-of-care cardiac ultrasound (parasternal short)
Figure 2. Point-of-care cardiac ultrasound (parasternal short)

Diagnosis

Heart Failure with Reduced Ejection Fraction. Bedside ultrasound demonstrated a small pericardial effusion and reduced left ventricular ejection fraction (LVEF). Estimating LVEF is important to rule out reduced cardiac output as the cause of dyspnea. Studies have shown that experienced emergency department providers are highly skilled at qualitatively visually estimating LVEF (e.g. reduced vs. normal) (1).

However, there are several problems with using visual ‘gestalt’ to estimate LVEF:

    1. It is not a quantitative measurement
    2. Visualization may be variable or inaccurate in newer sonographers (e.g. medical students, new residents)

Thankfully, there is a quantitative measurement of LVEF that can be obtained and has been validated: the e-point septal separation (EPSS) (2-4). EPSS is measured by obtaining a parasternal long axis view (for more on this, check out our basic cardiac lecture) and placing the M-mode line across the distal tip of the mitral valve. A ‘waveform’ of the mitral valve movement will be displayed (Figure 3).

Obtaining the e-point septal separation
Figure 3. Obtaining the e-point septal separation (adapted from coreultrasound.com)
Calculation and Correlation of EPSS with LVEF
Figure 4. Calculation and Correlation of EPSS with LVEF (from our Advanced Cardiac lecture)

The peak of the waveform is termed the E-point and is the point at which the mitral valve opens. This represents early diastolic filling and when flow across the mitral valve is maximal. There is a second peak called the A-point, which represents brief increased flow from atrial kick just prior to systole. A normally functioning left ventricle will squeeze down enough to get very close to the distal mitral valve when diastole begins, whereas a poorly functioning left ventricle is unable to contract enough, and thus are farther away from the valve. The distance between the E-point and the ventricular septum can be measured and used to estimate the LVEF. There is an inverse correlation between LVEF and EPSS—the greater the EPSS, the more poor the left ventricular function (Figure 4). An EPSS of greater than 10mm suggests a reduced ejection fraction, while values less than 7mm suggest a normal ejection fraction.

Our patient had an EPSS of approximately 20mm. He underwent a confirmatory echocardiogram and found to have an LVEF of 25%.

Limitations

Remember that there are two types of heart failure, with reduced (systolic) or preserved (diastolic) ejection fraction. EPSS may only be abnormal in cases where there is a reduced ejection fraction. However, in cases of preserved ejection fraction, patients may have a normal EPSS. Next, beware of several pathologies that may give you a falsely elevated EPSS, such as mitral stenosis (due to valve stiffness) and aortic regurgitation (backflow of blood into the left ventricle). With heart disease often comes valvular pathologies, so use the EPSS as a tool or adjunct alongside visualization and the overall clinical picture. Despite these limitations, studies have confirmed that providers with less experience can quickly learn how to obtain this measurement, and that measurements do correlate well with visual estimation (3-4).

Teaching Points

Measurement of EPSS can be used to estimate LVEF in emergency department providers with less experience while they build their visual gestalt. An EPSS greater than 10 mm suggests a reduced ejection fraction, while values less than 7 mm suggest normal ejection fraction.

References

  1. Unluer EE, Karagoz A, Akoglu H, Bayata S. Visual estimation of bedside echocardiographic ejection fraction by emergency physicians. West J Emerg Med. 2014;15(2):221-6.
  2. Ahmadpour H, Shah AA, Allen JW, et al. Mitral E point septal separation: a reliable index of left ventricular performance in coronary artery disease. Am Heart J. 1983; 106:21-8.
  3. Secko MA, Lazar JM, Salciccioli LA, et al. Can junior emergency physicians use E-point septal separation to accurately estimate left ventricular function in acutely dyspneic patients? Acad Emerg Med. 2011;18(11):1223-6.
  4. 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.