Anyone ever had a kitty with 'gallop rhythm' in the heart?

[mr_lebowski]

My boys pushing 17yo and the vet told me at his checkup (first in over a year) earlier in the week that she's hearing a gallop rhythm. I've looked it up on the web and understand there's some drugs that could help like diuretics and various other stuff, just wondering if anyone has any personal experience with it?

Vets are only taking emergency cases and all that seems wrong with him is his eating has gotten finicky lately and he's eating less as a result. And he's sleeping more.