MYOCARDIAL VELOCITY-GRADIENT AS A NEW INDICATOR OF REGIONAL LEFT-VENTRICULAR CONTRACTION - DETECTION BY A 2-DIMENSIONAL TISSUE DOPPLER IMAGING TECHNIQUE

Objectives. This study was performed to assess a new indicator of regi onal left ventricular contraction determined by a two-dimensional tiss ue Doppler imaging technique. Background. Recent studies have demonstr ated that instantaneous tissue motion velocity can be noninvasively as sessed by tissue Doppler imaging. However, quantitative assessment of regional left ventricular contraction is still difficult because of th e effects of the Doppler angle of incidence and parallel motion of the whole heart. Methods. We assessed left ventricular wall motion in 11 normal subjects, 14 patients with an old myocardial infarction (antero septal in 7, posterior in 7) and 8 patients with dilated cardiomyopath y. Tissue Doppler velocity was corrected by the Doppler angle of incid ence after the hypothetical center of contraction was set. Subsequentl y, the myocardial velocity gradient between the endocardium and epicar dium was determined from the velocity profile along each radial line f rom the center of contraction by using least squares linear regression . Results. In normal subjects, peak myocardial velocity gradient was l ower in the anteroseptal wall (mean [+/-SD] 1.69 +/- 0.53 s(-1)) than in the posterior wall (3.28 +/- 0.67 s(-1), p < 0.01). Myocardial velo city gradient in the infarct regions was significantly lower (anterose ptal 0.58 +/- 0.41 s(-1), p < 0.05; posterior 0.17 +/- 0.27 s(-1) p < 0.01) than that in normal subjects as well as that in the correspondin g noninfarct regions (2.84 +/- 0.37 s(-1) and 1.48 +/- 0.25 s(-1), p < 0.01, respectively). In patients with dilated cardiomyopathy, myocard ial velocity gradient was generally lower (anteroseptal 0.72 +/- 0.59 s(-1); posterior 0.93 +/- 0.67 s(-1)) than that in normal subjects (p < 0.01). Conclusions. These results demonstrate that regional left ven tricular contraction can be quantitatively assessed by the myocardial velocity gradient derived from two-dimensional tissue Doppler imaging. We suggest that myocardial velocity gradient has potential for the qu antitative assessment of regional left ventricular contraction abnorma lities in patients.