What is the blood flow direction in a child with an ASD?

In a child with an atrial septal defect (ASD), the blood flows from the left atrium to the right atrium. This occurs because the left atrium typically has higher pressure compared to the right atrium during systole. As a result, oxygen-rich blood from the left atrium can pass through the ASD and enter the right atrium. This leads to an increased volume of blood in the right atrium and subsequently the right ventricle, causing increased blood flow to the pulmonary circulation.

This left-to-right shunting of blood can result in overcirculation of the lungs, which may lead to pulmonary congestion and eventual complications if not addressed. Understanding the hemodynamics is crucial for assessing any potential impact on the child’s cardiovascular system and for considering treatment options.