Tricuspid Insufficiency

I have a 12 year old son who was diagnosed with tricuspid insufficiency 1-2+ and 2+ aortic insufficiency.  This was noted after his pediatrician heard a very slight murmur.  He sees a pediatric cardiologist once a year.  He has no symptoms is in great shape and feels great.  His doctor told me that he can do any competitive sport except football, weight lifting and wrestling.  We just moved to another State and his new cardiologist said the same thing.  He is now into competitive swimming and just recently at a meet had severe shortness of breath where he could not continue the race.  Could this be related to his heart problem?  I called his cardiologist and he told me that competitive swimming  should be no problem.  I hope he's right... the kid is really good at it and might have a career in this.  Any ideas?  Should I consult another cardiologist?