Images were yzed using the 4-dimensional LV-ysis software (TomTec Imaging Systems, Unterschleissheim, Germany) for quantification of global ventricular function and regional mechanical dyssynchrony. Three apicalviews (4-, 3-, and 2-chamber) were identified, and the LV endocardial boundary was manually traced on the first frame of the sequence corresponding to end-diastole and a frame depicting the allest LV cavity, roughly corresponding to end-systole. During tracing, the papillary muscles and endocardial trabeculae were included in the LV cavity. Then,the LV endocardial surface was automatically reconstructed frame-by-frame throughout the cardiac cycle and corrected manually if necessary. From these surfaces, a curve of LV volume over time was generated. From these volume–time curves, enddiastolic volume (EDV) and end-systolic volume(ESV) were derived as maximum and minimum values, and EF was calculated.
