Usefulness of myocardial velocity gradient derived from two-dimensional tissue Doppler imaging as an indicator of regional myocardial contraction independent of translational motion assessed in atrial septal defect

Although echocardiography permits noninvasive visualization of left ventricular wall motion, objective and quantitative evaluation of regional myocardial contraction is still problematic with currently available techniques.(1-6) Tissue Doppler imaging is a new technique that has been developed for the evaluation of myocardial motion in real time.(7-10) Attempts have been made to quantitate regional wall motion by using velocities derived from tissue Doppler imaging(8,10,11); however, because Doppler-measured velocities are affected by translational motion as well as by the Doppler angle of incidence, these effects simply cannot pass unnoticed in the quantitation process of regional myocardial contraction.(10,12-15), Although a recently introduced tissue Doppler indicator, myocardial velocity gradient, is unlikely to be affected by the translation from theoretical considerations,(16) its translation independence has not been validated in clinical settings. Patients with uncomplicated atrial septal defect have preserved left ventricular contraction with exaggerated translation of the left ventricle.(17-20) Therefore, if normal myocardial contraction in patients with uncomplicated atrial septal defect can be demonstrated by using myocardial velocity gradient, the translation independence of myocardial velocity gradient is validated. Thus, we sought to validate the translation independence of the myocardial velocity gradient by comparing normal subjects and patients with uncomplicated atrial septal defect.