Which chamber of the heart does the left-to-right shunt primarily affect in ventricular septal defects?

In the context of a ventricular septal defect (VSD), which is a congenital heart defect characterized by an opening in the ventricular septum, a left-to-right shunt occurs. This means that blood flows from the left ventricle to the right ventricle due to the pressure differential, as the left ventricle typically generates higher pressure than the right.

When this shunt takes place, a significant volume of blood will return to the right ventricle. Consequently, this increased volume can lead to over-circulation in the right side of the heart and the pulmonary circulation. Over time, this can cause the right ventricle to enlarge and become hypertrophied due to the extra workload.

While the left atrium and left ventricle are involved in the initial shunting process, it is the right ventricle that is directly affected by the increased volume flow resulting from the left-to-right shunt in VSD. Therefore, the right ventricle experiences the most significant change due to this condition, ultimately influencing its function more than the other chambers of the heart.