ASD is a common left-to-right shunt congenital heart disease, and blocking ASD with Amplatzer blocker corrects the anatomical malformation, which will certainly lead to hemodynamic changes and have certain effects on cardiac function. The left ventricular shape tends to be narrower and in severe cases, it even shows “slit-like” changes, resulting in an increase in the left ventricular eccentricity index compared with normal subjects. After ASD occlusion, tricuspid diastolic flow velocity and pulmonary artery systolic flow velocity decreased, while mitral diastolic flow velocity increased, suggesting that ASD occlusion can rapidly reverse the hemodynamic changes of ASD. The increase in left ventricular volume per beat, left ventricular ejection fraction and SF suggested improvement in left ventricular systolic function. The left ventricular eccentricity and L/D were significantly smaller than before surgery, suggesting that the left ventricle was closer to an ellipse than before surgery, and the left ventricular geometry was significantly improved. 3 and 6 months after ASD occlusion, the anteroposterior diameter and end-diastolic volume of the left ventricle increased, and the left ventricular ejection fraction and SF increased further. It is suggested that as the right heart volume load changes, the right heart size and volume progressively improve, the abnormal septal motion decreases or disappears, the work of the left ventricle is enhanced, the pressure on the left ventricle is reduced, the left ventricular size progressively improves, and the left ventricular dilatability increases, which further optimizes the left ventricular preload, left ventricular size, and left ventricular geometry, and thus the left ventricular function continuously improves. The improvement of left ventricular systolic function in the early post-occlusion period was mainly due to the increased blood flow back to the left ventricle after ASD closure and the improvement of preload. In conclusion, the interventional treatment of atrial septal defect not only cured the congenital anatomical malformation and corrected the hemodynamic abnormality, but also improved the systolic function and geometry of the left ventricle.