nervous/anxious
I'm so sorry you are having to go through this. Please try to not worry too much. Many people have murmurs that cause no problems. It is just necessary precaution. And, if it is something, much better to find out now-before anesthesia and surgery. I know, my words really mean nothing and it will weigh on your mind until you see the cardiologist, but try not to worry about what might be.
Please don't stress. They will probably do an ECHO Cardiogram just to see hoe efficiently your heart is pumping. The anesthesiologist needs to know this to plan accordingly. People have very serious surgeries with heart murmurs. The ones that don't show up until now are usually present from birth, and hardly discern able. Good luck with your sleeve.