took my cat for her yearly mot/injection and to my complete surprise vet said she has a heart murmur although he said quite mild, may have been born with it, on a scale of bad 1-6 he said she is about 2. still upset though. he is going to do a blood test to see if it is thyroid related. we have only had her for a year (rescue cat), gutted really, was hoping she would be one of those cats that lives to be really old, doubt it now. anyone else have a cat with a heart murmur?