Assessment of left ventricular function by different speckle-tracking software

Two-dimensional (2D) speckle echocardiography enables objective assessment of left ventricular function through the analysis of myocardial strain, which can be measured by different speckle-tracking software. The aim of this study was to compare two different commercially available cardiac ultrasound systems and their manufacturer-specific speckle-tacking software for the quantification of global myocardial strain in a healthy population. Twenty-eight healthy subjects (age: 38 +/- 12, 64% males) underwent two 2D echocardiograms within the same day using different cardiac ultrasound systems: Vivid 7 (GE Ultrasound, Horten, Norway) and Artida 4D (Toshiba Medical Systems). Standard apical and short-axis views of the left ventricle were obtained in each subject with a frame-rate range of 60 +/- 20 frames/s. Global longitudinal, radial, and circumferential strain values were analysed using their respective speckle-tracking software for Vivid (2D-strain EchoPac PC v.7.0.1, GE Healthcare, Horten, Norway) and Toshiba systems (2D Wall Motion Tracking, Toshiba Medical Systems). Global strain values were estimated from the average of regional left ventricular strain values. Agreement between the two systems and software was assessed by Bland-Altman method. Mean left ventricular ejection fraction was 59 +/- 7%. Global longitudinal, radial, and circumferential strain values were, respectively, -21.95 +/- 1.8, 46.97 +/- 5.5, and -23.18 +/- 3.3% when using 2D-strain EchoPac and -22.28 +/- 2.1, 40.74 +/- 4.3, and -27.17 +/- 4.7% when 2D Wall Motion Tracking was used (P = NS). Limits of agreement between both speckle-tracking software were narrower for global longitudinal strain (-2.25 to 3.65) than for radial and circumferential strain (-2.23 to 12.44 and -1.36 to 10.54, respectively). Two commercially available speckle-tracking software appear to be comparable when quantifying left ventricular function in a healthy population. Global longitudinal strain is a more robust parameter than radial and circumferential strain for the assessment of myocardial function when different cardiac ultrasound systems are used for analysis.