Background: Based on color Doppler methodology, regional myocardial strain rate (SR) and strain (epsilon) can now be calculated by comparing local myocardial velocity profiles. These deformation data sets may be an important new approach to quantify regional function of the left or right ventricle in congenital heart disease. The aim of the present study was to provide normal value for epsilon and SR in pediatric age.
Methods: We studied 45 healthy subjects (25 males, 20 females, mean age 11 +/- 6 years, range 4-16 years). For each subject we measured regional peak systolic, early and late diastolic E and SR.
Results: Left ventricular (LV) longitudinal deformations were homogeneous for LV basal, mid and apical segments (peak systolic SR -1.9 +/- 0.7 s(-1), systolic epsilon -24 +/- 8%). Longitudinal SR and epsilon values were significantly higher in the right ventricle, compared with LV walls, and were maximal in the mid part of the right ventricle free wall (peak systolic SR -3.4 +/- 0.9 s(-1), systolic epsilon -35 +/- 5%). The LV systolic and diastolic SR and epsilon values were higher for deformations in the radial direction compared with the longitudinal direction [radial peak systolic epsilon 55 +/- 6% vs longitudinal peak systolic epsilon (-)24 +/- 8%, p < 0.0001; radial peak early diastolic epsilon (-)40 +/- 15% vs longitudinal peak early diastolic epsilon 17.22 +/- 7%, p < 0.0001; radial peak systolic SR 2.7 +/- 0.5 s(-1) vs longitudinal peak systolic SR (-)1.9 +/- 0.7 s(-1); radial peak early diastolic SR (-)6.2 +/- 1.5 s(-1) vs longitudinal peak early diastolic SR 2.24 +/- 1.2 s(-1), p < 0.0001].
Conclusions: This study provides normal values for epsilon/SR in the largest published series of normal healthy children using a high frame rate (> or = 200 frames/s) and a commercially available software.