Abstract: Abstract Obiective： To evaluate left atrial asynchrony in patients with dilated cardiomyopathy (DCM) by real-time three-dimensional echocardiography (RT-3DE). Methods：Thirty-one patients with DCM and thirty healthy subjects underwent RT-3DE. Left atrial 16-, 12-, 6- segment models asynchrony parameters including the standard deviation（Tmsv 16-SD、Tmsv 12-SD、Tmsv 6-SD） and maximal difference of QRS to Tmsv（Tmsv 16-Dif、Tmsv 12- Dif、Tmsv 6- Dif）were measured, and maximun left atrial volume index(LAVmax index), minimum atrial volume (LAVmin index), volume before atrial active contraction (LAVpre index) were measured. Left atrial emptying passive atrial emptying fraction(LAEF), passive atrial emptying fraction (LAEFpassive), active atrial emptying fraction (LAEFactive) were calculated. Results： Left atrial 16-, 12-, 6- segment models asynchrony parameters were significantly higher in the DCM group than those in the control（P<0.05）. LAVmax index, LAVpre index and LAVmin index were higher, whereas LAEF, LAEFpassive、LAEFactive were lower in the DCM groups than those in the control group（P<0.05）. Moreover, there were correlation between left atrial 16-, 12-, 6- segment models asynchrony parameters and left atrial volume and function. There were positive correlations between left atrial Tmsv16-SD，Tmsv 16Dif and LAVmax index（r=0.71、0.74, P<0.01, respectively）, and negative correlations between left atrial Tmsv16-SD,Tmsv 16 Dif and EF（r=-0.69、-0.72, P<0.01，respectively）. Conclusion： RT-3DE is a useful ultrasonic technique that can allow accurate evaluation of left atrial asynchrony in patients with dilated cardiomyopathy, left atrial asynchrony have intenly relation with left atrial dilate and decrease atrial function.

Key words: cardiomyopathy, dilatedatrial function, leftechocardiography, three-dimensionalatrial fibrillationelectrocardiography Atrial, Synchronicity, 心电描记术