Congenital heart disease

As more and more of the children coming from China are special needs there is a great number of them that were born with problems of the heart. It is very hard to know how bad the problem is before getting the baby home and what will be needed to fix it. The initial surgery is often done in China but often a series of surgeries are needed to further rearrange the plumbing until the child is grown. Currently the survival of these children is around 80% from birth for all types of these heart problems as a whole.
So what are the problems if my baby has one of these congenital heart problems? 
Like everything there is good and bad news. The bad news is that when these babies have had scans done of their brains before surgery about 20% of them already have some damage that was done by the heart problem even before birth. The good news is that in long term studies of these children after the surgeries, they seem to do fine although their IQ's are slightly lower than other children. The other important factor is that the more well off economically and educationally the babies' families are the better they do probably because their families can access more help for the babies.
How is the heart built and why do these defects cause so much trouble? 
To get an idea of the hearts job think of the face of  a clock. At the top or 12 O'clock position is the right side of the heart which pumps blood, blood without oxygen toward 3 O'clock. At 3 O'clock are the lungs which add dissolved oxygen to the blood and send it along to 6 O'clock where the left side of the heart sits. The left side is the workhorse of the heart and pumps the blood now rich in oxygen to the 9 O'clock position for the rest of the body including the brain, kidneys, stomach, arms, legs. The brain loves oxygen and all the other organs are there to keep the brain well fed with oxygen. No oxygen and the brain dies. That is the basic plumbing of the body.
Now let's get a little more accurate detail. If you take your fingers and pinch the 12 O'clock down to the 6 o'clock  you end up with a figure of 8. This is really what happens because the left and right parts of the heart are directly next to each other but the blood  normally can't get from one side to the other. If you throw in a hole between the two sides or remove the 12 o'clock position altogether you see that the oxygen rich blood gets mixed with the other blood and gets pumped out to the body. Sometimes both sides of the figure 8 don't connect at all so there is only bad blood on one side and good blood on the other with only a tiny hole connecting the two sides. This is why the surgeries are so complex and take multiple steps because the plumbing can get really crazy!
So how do they work on a pumping heart anyway? 
They either stop it and work fast or they bypass the heart and let a machine do the pumping. This is called cardiopulmonary bypass and is done by putting a tube in at 11 O'clock and taking all the blood out before it gets to the right side of the heart and running it through a machine where they add the oxygen that it would normally get from the lungs at 3 O'clock. It is then run back into the body at 7 O'clock thus bypassing the heart altogether. The body and most importantly the brain get the oxygen it needs and the surgeon can work on the heart without it pumping away.