Which congenital heart defect causes increased pulmonary blood flow?

Increased pulmonary blood flow occurs when there is an abnormal connection that allows blood to flow from the left side of the heart to the right side, resulting in excess blood being sent to the lungs. An atrial septal defect is characterized by a hole in the septum that separates the two atria, permitting oxygen-rich blood from the left atrium to mix with oxygen-poor blood in the right atrium. This causes increased volume in the right atrium and subsequently increases blood flow to the pulmonary circulation, leading to elevated pressure in the lungs over time.

Other congenital heart defects listed do not typically result in increased pulmonary blood flow. Aortic stenosis involves narrowing of the aorta, which primarily affects blood flow to the systemic circulation rather than increasing flow to the lungs. Tricuspid atresia is associated with a lack of connection between the right atrium and the right ventricle, leading to reduced blood flow to the lungs and potential for decreased pulmonary perfusion. Coarctation of the aorta causes a narrowing of the aorta, impacting overall systemic circulation rather than resulting in increased pulmonary flow.

Thus, among the options provided, an atrial septal defect is the most straightforward example of a condition that directly leads to increased