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 (3DLε), circumferential strain (3DCε), radial strain (3DRε), and area strain (3DAε) 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 3DLε, -17% to -20% (-14%) for 3DCε, -31% to -36% (-26%) for 3DAε, and 47% to 59% (38%) for 3DRε. Three-dimensional longitudinal strain decreased, whereas 3DCε increased, with aging (P < .003), with different trends in men and women. Men had lower 3DLε, 3DRε, 3DAε, 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 3DCε and 3DRε 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.