Kitty with heart murmur

I just sent in a question…this one is about the same kitty. When he had his one year old check up at the vet she listened carefully to his heart and then said that he had a murmur. She even gave it a “class”, and recommended an ultrasound. I did have the ultrasound done and she did not find any problem. Do you think I should investigate more. Or could he have just been soooo excited at the visit that it presented as a murmur?