Abstract: Background：Changes in diastolic function are usually the first to occur when there is abnormal cardiac function. Currently, although there are many studies on ventricular systolic function, there is limited research on the changes in left ventricular diastolic function in congenital heart disease (CHD). Objective：To assess left ventricular diastolic function indices of CHD with lefttoright shunt before and after interventional therapy using echocardiography. Design：Selfcontrolled beforeafter trial. Methods：The case group of this study included pediatric patients under 18 years old who were diagnosed with patent ductus arteriosus (PDA), ventricular septal defect (VSD), or atrial septal defect (ASD) and underwent interventional treatment at the Children's Hospital of Chongqing Medical University. Patients with complex CHD, congenital developmental abnormalities, or genetic metabolic diseases were excluded from the study. Healthy children were recruited as the control group. Multiplesectional echocardiographic scans were performed on the lower sternal border, parasternal area, and suprasternal area to collect left ventricular diastolic function parameters (including left ventricular structure, blood flow spectrum for mitral valve and pulmonary veins, and tissue Doppler motion spectrum for mitral annular) as well as general information (age, height, weight, body surface area) during the ultrasound examination. Left ventricular function parameters in the case group were compared within 1 week before intervention surgery, 1 day after the surgery, and 1 month after the surgery to analyze the changes by taking the parameters of healthy children as the reference. Main outcome measures：Recovery levels of left atrial volume index (LAVI), early diastolic mitral flow peak velocity(E)/late diastolic mitral flow peak velocity(A) ratio, E/early diastolic mitral annular peak velocity at ventricular septum(E') ratio, and E/early diastolic mitral annular peak velocity at lateral wall(e') ratio after interventional therapy. Results：A total of 163 cases of CHD patients were included. There were 60 cases in the PDA subgroup, 42 cases in the VSD subgroup, and 61 cases in the ASD subgroup. A total of 61 healthy children were recruited for the control group. The PDA and VSD subgroups had significantly lower age, height, weight, and BSA compared to the control group. In the PDA, VSD, and ASD subgroups, LAVI, E/A ratio, E/e' ratio and E/E' ratio for mitral annular by tissue Doppler motion spectrum were significantly higher than those in the control group before the procedure with statistical significance. These indices decreased 1 day after the procedure and returned to the level of the control group 1 month after the procedure. The pulmonary vein flow spectrum D showed a decreasing trend before the procedure, 1 day after the procedure, and 1 month after the procedure, with a lower level in the control group 1 month after the procedure. Conclusion：Echocardiography can be used as an assessment tool for left ventricular diastolic function in children with common left-to-right shunt type CHD. There are varying degrees of left ventricular diastolic dysfunction in PDA, VSD, and ASD, which can be improved by interventional treatment, and can recover to almost normal levels after 1 month.

Key words: Echocardiography, Congenital heart disease, Patent ductus arteriosus, Ventricular septal defect, Atrial septal defect, Left ventricular diastolic function