Which of the following is an example of left-to-right congenital heart disease?

An atrial septal defect (ASD) is characterized by an abnormal opening in the interatrial septum, allowing blood to flow from the left atrium to the right atrium. This results in a left-to-right shunt, which means that oxygenated blood from the left side of the heart bypasses the systemic circulation and instead flows into the right side of the heart. Consequently, this increased volume in the right atrium and right ventricle can lead to increased pulmonary blood flow, pulmonary hypertension, and right heart enlargement over time if left untreated.

In contrast, pulmonary stenosis involves narrowing at the level of the outflow tract of the right ventricle, which causes pressure overload in the right ventricle but does not create a left-to-right shunt. Transposition of the great arteries is a condition resulting in two separate circulatory systems, where the aorta and pulmonary artery are swapped, leading to a lack of adequate oxygenation and not a left-to-right shunt. Tetralogy of Fallot consists of four congenital defects and includes a right-to-left shunt, which diverts deoxygenated blood into the systemic circulation. Therefore, the ASD is the prime example of a left-to-right congenital heart defect