A ventricular septal defect, or VSD, is the most common kind of congenital heart defect. Normally, blood entering the right side of the heart stays on the right side (this is low-oxygen blood), and blood on the left side of the heart stays on the left side (this is oxygen-rich blood) which is then pumped to the rest of the body. When a defect or "hole" is present between the ventricles (or lower chambers), blood from the left side of the heart is forced through the defect to the right side every time the heart beats. It then goes back to the lungs even though it is already rich in oxygen. Because of this, blood that is not yet oxygen-rich can't get to the lungs. The most common signs and symptoms are trouble eating and gaining weight, breathlessness and easy fatigability. A baby with a large VSD tires quickly after not eating very much, falls asleep, wakes us in a short while quite hungry, tries to eat again, tires easily, and the cycle is repeated. Because the heart has to pump extra blood, it may enlarge. Also, because there's more blood going to the lungs, high pressure may occur in the blood vessels there. This may cause permanent damage to the walls of the blood vessels over time. Many, if not most, of all VSDs will close on their own. Those that close on their own are usually small and do so in the first year of life. Large VSDs, especially those that don't close in the first year of life, will usually need to be closed surgically. VSD closure is one of the most commonly performed congenital heart operations. The child would be expected to have virtually normal growth, development, and life expectancy following repair.