Measure the End-Systolic and End-Diastolic LV EDA. The optimal view is the LVSA view from the mid Transgastric acoustic window. The left ventricular area should be traced in end-diastole and end-systole. The difference of the the two, divided by the left ventricular end-diastolic area is the fractional area change. Note that the fractional area change is NOT the ejection fraction. Ejection fraction is based upon (extrapolated) volumes whereas the FAC is based upon area. Therefore, values of FAC will be less than the ejection fraction. See below for a comparison.