Reviewed by Michael Fuller, MDASD is one of the most common congenital heart disorders. In children with ASD there is a hole in the wall (septum) between the left and right atria. This hole allows blood to move from the left atria to the right, which can cause problems with heart and lung function. This condition is not as serious as a ventricular septal defect, and the hole often closes on its own.
An atrial septal defect is a hole in the wall (septum) between the right and left atria. It allows blood to travel from the left atrium to the right. This means excess blood is circulating in the right side of the heart, and in the lungs. This causes extra work for the right ventricle, which can cause it to enlarge. This is called cardiomyopathy, and it is usually not serious when associated with ASD. The overwork and heightened blood pressure (pulmonary hypertension) can also damage the blood vessels in the lung.
