Left ventricular deformation and two-dimensional echocardiography: temporal and other parameter values in normal subjects.

Segmental contractility can be assessed quantitatively by analyzing deformation, or strain, and the rate of deformation, or the strain rate. This type of analysis can be performed using either tissue Doppler imaging or, more recently, two-dimensional speckle-tracking echocardiography. The aim of this study was to determine typical parameter values in healthy subjects and their reproducibility. The study involved 105 healthy individuals, including 55 women (52.45%). Their mean age was 38.8 ± 9.5 years (range, 20-59 years). All underwent speckle-tracking echocardiography with velocity vector imaging. Mean values for the strain and strain rate for each segment as well as for the time-to-peak normalized by the length of the cycle (TPN) were obtained. The resulting mean values were: circumferential strain, 22.2 ± 4.81% with a TPN of 0.39 ± 0.06; longitudinal strain, 19.84 ± 4.59% with a TPN of 0.42 ± 0.06; circumferential strain rate, 1.64 ± 0.48 1/s with a TPN of 0.23 ± 0.06; and longitudinal strain rate, 1.3 ± 0.49 1/s with a TPN of 0.21 ± 0.09. Intra- and inter-observer variability were moderate in magnitude.