Objective To evaluate the impact of Z-score of early diastolic velocities using tissue Doppler imaging(TDI) in children with dilated cardiomyopathy(DCM) . Methods Fifty-eight children with DCM and 58 healthy children (control group) were selected ,tissue Doppler velocities were converted to Z-score on the basis of body-surface-area-adjusted . The Z-score head-to-head with the raw velocities were compared.Results ①Lateralwalle'velocitiesandinterventricularseptale'velocitieswerepositively correlated with age ( r = 0 .710 ,0 .622;all P < 0 .05 ) . Tissue Doppler velocities and Z-score of mitral annular in DCM children were lower than the normal children( P <0 .001) . ② The discriminant capacity was higher for the Z-score than for the e'raw velocities ,which were assessed by the area under the receiver operating characteristic curves . Conclusions The Z-score of early diastolic velocities are better than the raw velocities in evaluating left ventricular diastolic function in children with dilated cardiomyopathy

The children with dilated cardiomyopathy (DCM) are in the different stages of growth and development,so the measurements of the cardiac size and the function in the echocardiography can change with those growth and development.But the influence factors of growth and development had been ignored by the previous standards,which was not conducive to evaluate the efficacy of drugs and the prognosis of patients.The disadvantages above can be overcome by converting the echocardiographic measurements into the Z score after correction of the body surface area.With the development of the ultrasonic technology,there have been some studies of the Z score combined with the ultrasound to assess the left/right ventricular heart function and prognosis in children with dilated cardiomyopathy.The progresses of Z score in children with dilated cardiomyopathy were reviewed in this article.