3D dataset acquisition and analysis
Real-time 3DE image acquisitions of the LV from the 4-chamber view were performed using echocardiographic ultrasound platforms (GE Vivid E9/E95; Vingmed Ultrasound, Horten, Norway, iE33/EPIQ; Philips Medical Systems, Andover, MA, USA, and/or Siemens SC2000, Siemens Medical Solutions, Malvern, PA, USA). 3D datasets were excluded by the core lab if any portion of LV endocardial borders or LV apex were not well visualized in the 3D dataset. LV end diastolic and end systolic volumes (EDV and ESV), stroke volumes (SV), and ejection fraction (EF) were generated after manually editing the contours to define the LV endocardial borders using semi-automated method (4D LV Analysis, TomTec Imaging Systems version 4.0, Unterschleissheim, Germany). The core laboratory performed intraobserver (LL – measured 6 months apart) and interobserver (LL and PNJ) variability in 20 randomly selected datasets.