
Just to clarify, dogs with herat problems don't have to have all or even several of those symptoms. :) I have a dog who has a VERY serious heart murmur indeed (my vet expected him to die 3 years ago but Rufus didn't think that was necessary thank you! :D ) and he can eat for England, is as happy as Larry, don't have a swollen abdomen (that would be due to a fluid build up), loves walks and training (but has to be limited) and doesn't cough much. He does sleep a lot though for sure. Yes he is on medication now, but the only reason for why his murmur was found was that I bought a stethoscope on Ebay and played around with it and heard it myself. So it can vary a lot from dog to dog. I have had others, in my personal experience the most common signs are tiredness, some dogs "faint" at times. Mine has little episodes of "mini fits" when he for a few seconds lose balance, my vet explained this with it happening when the heart doesn't pump the blood to the brain efficiently enough.
But to go back to the original question; no snorting has nothing to do with it. Some breeds do it more than others, and in fact in some cases it can partly be due to indigestion, i.e. an excess of stomach acids.
Take heart (no pun intended) both of you, these days there is so much they can do for dogs with heart problems, especially those that develop it when older. If one medication doesn't work there are others. Good luck! And Rufus say hello! :)