My son, who is now aged 4, was diagnosed with a heart murmur when he was 18 months old. At the time he too had a cold. After seeing various specialists, they decided that the murmur was innocent, and that he would probably grow out of it. One thing they advised though, just to be on the safe side, was if he was to undergo any operation of any type, that he should be given antibiotics at the same time. Maybe you should mention this to your doctor when you see them. I know how you feel, its terrible hearing your child has a heart problem, so I've got my fingers crossed for you, that it also turns out to be an innocent murmur. I was also told that it is pretty common in children. Let us know how you get on.