Our daughter was diagnosed with WPW when she was 8 months old, but the equipment to do the surgery was not available to us for her surgery until she was 17 months old. She was put on a medication "INDEROL" for 9 months. At the time of surgery she was in congestive heart failure and her liver and lungs were starting to fail. Dr. Campbell did the surgery at 17 months old and she has been great ever since. They did the surgery with very "Radio Frequency Ablation" and the instruments were so small, she came home with only band-aids. She was the only infant that had been diagnosed at this age. Normally it is something that is not diagnosed until they are older (like your sons' age). We have been on local news stations and medical reports and newspapers in Atlanta, Georgia. The 9 months leading up to her surgery were the hardest because we did not know what the outcome would be for her or if she would make it at all. Her heart rate would go up to 280 beats per minute. So fast you could not count the beats.
We still have her stethoscope....and she is almost 7 years old. It must be a mommy thing.
I consider you a friend also!! It is very hard dealing with something that you can not see, and even when the doctors talked to us about it, it was hard to understand. Everything will be alright. I am here for you and your family.
What kind of sports does your son like to play? Our daughter was too little to play sports at the time she was sick, but now you can't keep her from playing soccer or running around!! 
Please keep me informed, I would love to know what the doctors say. And please don't forget about Dr. Campbell, he is the best and so calming and reassuring. He made the entire situation bareable for her and us also. He was like an angel for us.
Talk to you soon - Heartmom