Left Ventricular Myocardial Strain by Three-Dimensional Speckle-Tracking Echocardiography in Healthy Subjects: Reference Values and Analysis of Their Physiologic and Technical Determinants

Background: Despite growing interest in applying three-dimensional (3D) speckle-tracking echocardiography (STE) to measure left ventricular (LV) myocardial deformation in various diseases, normative values for 3D speckle-tracking echocardiographic parameters and the effects of demographic, hemodynamic, and technical factors on these values are unknown. Methods: In 265 healthy volunteers (age range, 18-76; 57% women), longitudinal strain (3DL epsilon), circumferential strain (3DC epsilon), radial strain (3DR epsilon), and area strain (3DA epsilon) were measured by using vendor-specific (Vsp) 3D speckle-tracking echocardiographic equipment. LV strain was also measured by using Vsp two-dimensional (2D) and vendor-independent 3D speckle-tracking echocardiographic software packages, for comparison. Results: Reference values (lower limit of normality) for Vsp 3D STE were -17% to -21%(-15%) for 3DL epsilon, -17% to -20%(-14%) for 3DC epsilon, -31% to -36%(-26%) for 3DA epsilon, and 47% to 59% (38%) for 3DR epsilon. Three-dimensional longitudinal strain decreased, whereas 3DCe increased, with aging (P<.003), with different trends in men and women. Men had lower 3DLe, 3DRe, 3DAe, and 2D longitudinal strain than women (P<.02). LV 3D strain parameters were also influenced by LV volumes and mass, image quality, and temporal resolution (P<.02). Reference values obtained by Vsp 2D STE were -20% to -23% (-18%) for 2D longitudinal strain, -20% to -24% (-17%) for 2D circumferential strain, and 39% to 54% (28%) for 2D radial strain (P<.001 vs Vsp 3D STE). Significantly different 3DCe and 3DRe values were obtained with vendor-independent versus Vsp 3D STE (P<.001). Conclusions: In healthy subjects, reference values of LV 3D strain parameters were significantly influenced by demographic, cardiac, and technical factors. Limits of normality of LV strain by Vsp 3D STE should not be used interchangeably with Vsp 2D STE or with Vin 3D STE software.