Quantitative assessment of intrinsic regional myocardial deformation by Doppler strain rate echocardiography in humans.

Myocardial Deformation by Doppler Strain Rate Echocardiography in Humans To the Editor: We have read with interest the recent report of Edvardsen et al1 in which left ventricular regional peak systolic strain values measured by ultrasound were correlated with the corresponding strain data extracted by 3-dimensional tagged MRI. The study showed an overall acceptable agreement between the 2 techniques for several myocardial segments in both normal and pathological myocardium and for both radial and longitudinal deformation. Although the longitudinal deformation parameters measured were in agreement with prior results, the radial values were not. Indeed, in this study, Lagrangian radial strain in the posterior wall of healthy volunteers was measured to be 18 9% and 17 6% by ultrasound and MRI, respectively. However, previously reported studies using standard M-mode echocardiography had found radial maximal systolic Lagrangian strain values of 69 23%.2 The discrepancy between these values and the ones published in the study of Edvarsen et al1 could, in theory, be attributed to the fact that the authors used newer techniques based on MRI tagging and Doppler myocardial imaging, and that these techniques might be more accurate. However, previous cardiac MRI studies, both with and without tagging, had already shown Lagrangian radial strain in the posterior wall to be around 33 9% and 37 9%, respectively.3,4 Moreover, using Doppler myocardial imaging based strain estimation, values around 60 13% have been reported.5 Although a small decrease in radial strain with aging has been described,3 it cannot account for the large discrepancy with the values found in the study by Edvardsen et al. At least 4 independent studies using 4 different techniques have thus reported Lagrangian radial strain values of the posterior wall to be within the range of 35% to 60% for normal individuals around 40 years old. The values published in the paper by Edvardsen et al1 thus seem to be too low to be realistic for radial deformation in normal subjects. This might suggest that there is either a consistent methodological error in radial strain estimation in their paper (this is unlikely as both techniques gave similar values) or that the myocardial segment analyzed was too close to the fibrous mitral ring, as this region is known to deform less.