I don't second the second opinion. Theres no guarantee the second opinion will be more valid than the first unless the second doctor has expertise in sports related issues.

I can tell you that most doctors err on the side of caution, because we don't want to feel responsible for you hurting yourself.

Since doctor hunting can be time consuming and expensive, I wonder if there are web sites that give traiinng advice to heart patients. In theory there is no reason such web site shouldn't exist, although in practice, in America, most liability insurance coverage does not include advice given over the Internet.