Echocardiography
All echocardiographies were performed by a single investigator using the same ultrasound system (Vivid E9, GE healthcare), the same probe (M5S-D, GE) and the same analyzing software (EchoPac, version 203.66). Cine loops from 3 standard apical views (2-chamber, 4-chamber, and apical long-axis) were recorded using gray-scale harmonic imaging and saved in raw data format. Images were obtained at an acquisition rate of 50 to 90 frames per second. Left ventricular end-diastolic and end-systolic volumes and left ventricular ejection fraction (LVEF) were obtained using Simpson’s biplane method. For 2D-speckle tracking analysis, the inner endocardial borders were traced in the end-systolic frame in images from the three standard apical views. Speckles were tracked frame by-frame throughout the left ventricular wall during the cardiac cycle and basal-, mid-, and apical regions of interest were drawn (Fig. Off-line image analyses were independently performed by two investigators blinded to randomization allocation, clinical data and blood test results to reduce the risk of bias.
Measurement of Global Longitudinal Strain (A) and Mechanical Dispersion (B) from 2D-Speckle-Tracking software