What condition is associated with a left to right shunt in acyanotic CHD?

Atrial Septal Defect (ASD) is a condition that involves a left to right shunt in acyanotic congenital heart disease (CHD). In an ASD, there is an abnormal opening between the left and right atria, allowing blood to flow from the left atrium, which has higher pressure, to the right atrium, which has lower pressure. This results in increased blood flow to the right atrium and subsequently to the pulmonary circulation, leading to right heart volume overload.

The presence of a left to right shunt means that despite the mixing of oxygenated and deoxygenated blood, the systemic saturation remains relatively normal initially, which is characteristic of acyanotic heart defects. Over time, if left untreated, this condition can lead to consequences such as pulmonary hypertension and right heart failure due to the increased workload on the right ventricle.

In contrast, other conditions listed, such as pulmonary stenosis, transposition of the great vessels, and coarctation of the aorta, are either obstructive or cyanotic defects, not associated with a left to right shunt between the atria that characterizes ASD. This underlines the specific nature of ASD as it relates to the mechanism of blood flow and the