Hi Amy-
Let us know how things progress. Keep close track of his temp. even after going to the cardiologist, in case they elect to let things work out normally.
I hope that it's just a little bug and nothing more than that. Chances are that it is. However, everything means something with these folks, and Joe has had some very weird things develop after a moderately high temp like that.
Also keep checking for rashes or any other different things. Temps in an adult with heart valve problems are quite different than the same temp in a child.
You know your man, and if you don't like what you see, go to the ER. I'd rather have them think I'm a worry wart, than find out I should have taken Joe and didn't. His life has been saved a couple of times because we went sooner rather than later.
I now take Joe's temp every day in the morning and he weighs himself every morning, I also take his blood pressure each day and try to get a reading on the peak flow meter each day. I record all these things in a small notebook.
With a normal adult this would be overkill, but Joe isn't normal medically.