Which defect is most commonly associated with a ventricular septal defect?

A ventricular septal defect (VSD) is one of the most common congenital heart defects. It involves an opening in the ventricular septum that separates the left and right ventricles of the heart, leading to left-to-right shunting of blood. This increased flow into the right ventricle and subsequently into the pulmonary circulation can lead to various associated cardiovascular abnormalities.

Persistent ductus arteriosus (PDA) is closely related to VSD as both defects involve shunting of blood. When a VSD is present, there is an increased volume of blood flow to the lungs, which can promote the persistence of the ductus arteriosus. In normal physiological conditions, the ductus arteriosus closes shortly after birth. However, if there is elevated pulmonary blood flow as seen with a VSD, the ductus may remain open, leading to a PDA. This is why the association between VSD and PDA is commonly recognized.

The other conditions listed—atrial septal defect, coarctation of the aorta, and pulmonary artery stenosis—while they can occur in patients with various cardiac defects, they do not have the same direct association with VSD as PDA does. Thus, persistent ductus arteriosus is regarded