Age-Related Normal Range of Left Ventricular Strain and Torsion Using Three-Dimensional Speckle-Tracking Echocardiography

Abstract

Three-dimensional (3D) speckle-tracking echocardiography (STE) is an emerging technology used to quantify left ventricular (LV) function. However, the accuracy and normal values of LV strain and twistusing 3D STE have not been established in a large group of normal subjects. The aims of this study were to (1) to evaluate the accuracy of 3D STE analysis of LV strain against a cardiac magnetic resonance (CMR) reference and (2) to establish age-related normal values of LV strain and torsion using real-time 3D echocardiographic (RT3DE) images. In protocol 1, RT3DE data sets and CMR images were acquired on the same day in 19 patients referred for clinically indicated CMR. Global LV longitudinal, circumferential, and radial strain was compared between the two modalities. In protocol 2, global and regional strain and twist and torsion were measured in 313 healthy subjects using 3D STE. In protocol 1, good correlations for each LV strain component were noted between RT3DE imagingand CMR (r= 0.61-0.86, P < .001). In protocol 2, normal global longitudinal, circumferential, radial,and 3D strain were -20.3 ± 3.2%, -28.9 ± 4.6%, 88.0 ± 21.8%, and -37.6 ± 4.8%, respectively. A significant age dependency was observed for global longitudinal and 3D strain. Aging also affected LV torsion: the lowest values were found in children and adolescents, and values subsequently increased withage, while further aging was associated with a gradual reduction in basal rotation accompanied by an increase in apical rotation. This study provides initial validation of 3D strain analysis from RT3DE images and reference values of normal 3D LV strain and torsion. The age-related differences in LV strain and torsion may reflect myocardial maturation and aging.