What is the usual direction of blood flow across a Ventricular Septal Defect?

The usual direction of blood flow across a Ventricular Septal Defect (VSD) is from the left ventricle to the right ventricle. This is because the pressure in the left ventricle is typically higher than the pressure in the right ventricle. As a result, blood will flow from the area of higher pressure (left ventricle) to the area of lower pressure (right ventricle) through the VSD.