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Figure 1 Image of on-line derivation of beat-to-beat changes in the left ventricle area throughout the cardiac cycle, obtained from the parasternal short-axis view using automated border detection by echocardiography. The inherent computer software algorithm allows instantaneous calculation of the fractional area of change (FAC), as well as the maximal rate of rise of LV pressure (+dA/dt) and –dA/dt normalized to the LV end-diastolic area. EDA = end-diastolic area; ESA = end-systolic area; PER = peak emptying rate; PFR = peak filling rate; TPFR = time to peak filling rate.