Which congenital heart defect involves a flaw in the septum that divides the two atria of the heart?

Atrial septal defect (ASD) is characterized by a congenital defect in the septum that divides the two atria of the heart. This defect leads to an opening between the left and right atria, allowing oxygen-rich blood from the left atrium to flow into the right atrium instead of moving to the left ventricle and being distributed to the body. This abnormal blood flow can cause several complications, including increased pressure in the right atrium and pulmonary circulation, potential enlargement of heart chambers, and even heart failure or arrhythmias if left untreated.

In contrast, aortic valve stenosis pertains to a narrowing of the aortic valve, which affects blood flow from the heart to the aorta. Patent Ductus Arteriosus (PDA) involves a persistent opening between the pulmonary artery and the aorta after birth, which should normally close shortly after delivery. Ventricular septal defect (VSD) refers to a defect in the septum that separates the two ventricles, not the atria. Each of these conditions presents distinct issues, but only ASD directly involves a flaw in the septum between the atria.