fig20

Figure 20. Selected video frames from apical four-chamber location demonstrating the left ventricle in end-diastole (LVED) in (A) and in end-systole (LVES) in (B). Left ventricle (LV) area shortening may be calculated utilizing Simpson’s rule. Area shortening of the LV in this example is 52% (see insert in B). Standard values are 55% to 75% (see text for details). Reproduced from Ref.^[19].