Speckle tracking imaging measuring software will be used for offline analysis of
transesophageal echocardiogram (TEE) -acquired images of the left ventricle(LV) in four
chambers(4C), two chambers (2C) and long axis (LAX) views to calculate global longitudinal
strain (GLS) of LV for comparisons between sevoflurane and isoflurane at the same minimum
alveolar concentration ( MAC) levels.