This may sound frivolous, but it isn't meant that way.
Our 'rescue cat' from the local Animals' Shelter has a heart murmur. Over the last 5-6 years she has bounded around happily, and it seems her murmur is actually diminishing. She's certainly not called "Storm" for no reason - 100% is her standard mode of operation.
The problem will be the Doc who does the final assessment. Good luck!