The difference between a ventricular septal defect and an atrial septal defect mainly lies in their locations. A normal heart is divided into four chambers, which are the left ventricle, right ventricle, left atrium, and right atrium. Each chamber is separated by a septum, much like walls between rooms in a house. Due to certain reasons, such as congenital heart defects, there may be openings or defects in these walls, known as septal defects. An atrial septal defect refers to a defect between the right atrium and the left atrium, whereas a ventricular septal defect pertains to a defect between the left and right ventricles. The murmur of atrial septal defects is relatively softer, as the pressure difference between the atria is smaller, and the defect is located higher up. In contrast, the murmur of ventricular septal defects is louder due to the greater pressure difference between the ventricles and is located lower down, approximately between the third and fourth ribs. The murmur of atrial septal defects is found between the second and third ribs. Moreover, since the pressure difference in ventricular septal defects is greater, the impact on the heart is relatively more significant.