Description

Ejection fraction provides a quantitative assessment of left ventricular function in the presence of paradoxical septal motion. Of the many mathematical methods, Simpsons rule has been shown to be the most accurate. This method involves manual tracing of the LV cavity endocardium at end-systole and end-diastole, from the apical 4-chamber view and the apical 2 chamber view (the Biplane Simpson's Method). The machine's software then divides the cavities into many parallel discs, calculate the volume of each disc and automatically combines the volume to provide the user with estimated LV cavity volume in end diastole (LVEDV) and end systole (LVESV). Simpson's rule assumes the LV cavity to be ellipsoidal at all times. Normal value of EF in newborn infants is between 55-65%. It should also be recognized that both SF and EF are affected by changes in loading conditions The apical 4 chamber view is used as a starting point. Most modern machines have an option to measure ejection fraction using Simpson's biplane method. The LV cavity in the 4 chamber view is traced at the end of diastole (maximal area) and then at the end of systole (minimal area). The probe is then angled anticlockwise until the RV chamber is no longer visible to obtain the 2 chamber view (see video). The LV cavity is traced again in systole and diastole. The machine's software then should calculate the ejection fraction (See image).