As others have mentioned, the age of the kid will make all the difference. My younger son was born with a severe heart defect. His first three years were hellish, and then he had his last open heart surgery during the summer before kindergarten. He went through months of severe anxiety, and he still (a year and a half later) is less confident than his older brother. He is also very sociable, but not as rough-and-tumble as most of the boys in his class. He gets along with most kids, but he's a follower, not a leader. I can't imagine him being in a class of older kids--socially, he would not fit in despite being very sociable and generally getting along great with his older brother. But then, he isn't in the gifted range, and I suspect he might be borderline ADD (which is fairly common following open heart surgery). Depending on what your son has been through heart-wise, this may just not be a good time for major changes.