I would have to agree with almost everyone else that said to look for a new vet. If your current vet can not or will not take the time to answer your concerned questions then get someone new.

As for the enlarged heart. I have some experience with that. My 12 year old girl Tigger has an enlarged heart. We just had an ultrasound on her heart and she was a rating of a 2 out of 5, with 5 being the worst on the scale. Her enlarged heart is genetic as her brother Tony had cardiomyopathy which ultimately he lost his battle with that condition.

Tigger leads a very normal life. She does everything that every other kitty does in my house. However I do watch her carefully when it comes time to play as she loves to play and sometimes she gets so excited that I have to give her a time out so she can catch her breath.

I hope everything works out OK.