What is it?

-A ventricular septal defect (VSD) is a hole in the ventricular septum, the wall dividing the left and right ventricles of the heart. VSD's are usually congenital (present at birth) and they vary in size. They may be an isolated finding or associated with other conditions.
-An atrial septal defect (ASD) is a hole in the wall (septum) that separates the two atria of the heart. In the fetus, there are openings in this wall that close before birth. Atrial septal defect is a condition in which these openings have not closed properly and a hole remains. As a result, blood continues to flow between the two sides of the heart. In some cases, the atrial septal defect is small, asymptomatic and may even close on its own. In other cases, and especially if there is a significant shunt, the abnormal flow may put a significant strain on the heart over time, and cause the development of heart or lung disease. Therefore, it is important to diagnose and fix the atrial septal defect at a young age and thus prevent future problems.
-Tetralogy of fallot (TOF) is a rare condition, characterized by a combination of four heart congenital defects. These defects result in poor oxygenated blood to travel to the body, and that’s why the skin may appear bluish. Depending on its severity, tetralogy of fallot may be detected soon after birth, or even in adulthood. The four abnormalities include: pulmonary valve stenosis, VSD, overriding aorta and right ventricular hypertrophy. This condition may be accompanied by other heart defects. Risk factors include maternal virus illness, such as rubella, alcoholism and poor nutrition in pregnancy, older maternal age, a parent with TOF, or a child who has Down syndrome or DiGeorge syndrome.