Objective To explore the quantitative standard of left ventricular（LV）regression

analyze the factors that affect the effect of LV retraining

and to evaluate the effect of arterial switch surgeration（ASO）.MethodsEighty-six children with intact ventricular septal/transposition of great artery（TGA/IVS）were collected.43 received LV retraining and the second staged ASO（group A）

and 43 received one-staged ASO（group B）. The LV anterior-posterior diameter（LVEDd）and Z value

LV mass index

LV pressure regression rate

LV mass index degradation rate

and LV to right ventricular pressure ratio（LV/RV）were measured and calculated.The difference of the above parameters between the two groups were compared

the condition of children receiving ASO were followed up

Logistic regression analysis of factors affecting the effect of left ventricular training was analyzed

the correlation between each echocardiographic parameter and LV/RV was analyzed

and receiver operating characteristic curve was drawn determine the indicators of ASO timing and its effectiveness.Results ventricular septum showed"D"type

35 cases of ventricular septum showed"banana"type

and ventricular septal morphology of children in group B were normal.The ventricular septal morphology

ages

LV mass index

the Z value of LVEDd and LV/RV were statistically differenct between the two groups（all P<0.05）.Among the 43 children in group A

10 patients completed ASO within10 d of training

31 patients completed ASO on average 281.6 d after training

and 2 patients completed ASO after receiving pulmonary artery bandings twice.Logistic regression analysis showed that the age of the child’s visit was an independent factor affecting the success of LV retraining.Correlation analysis showed that the Z value of LVEDd

LV mass index were positively correlated with LV/RV（r=0.602

0.676

both P=0.0001）.The best ultrasound index for judging the timing of staging ASO was the LV mass index

followed by the Z value of LVEDd.The diagnostic cut-off values were 59.7 g/m2 and-1.45

respectively.The area under the curve were 0.97 and 0.93

and the sensitivity were 88.9% and 88.9%

the specificity were 97.4% and 82.1%

respectively.Conclusion ASO operation

the age of the child’s visit is an independent factor that affects the success of LV retraining.LV retraining is safe and effective

and can provide the treatment opportunities for the TGA/IVS children with LV regression.