
My vegan dog would be no good on raw, whenever he gets hold of something he shouldn't (including a pound of raw mince once), he ends up with dandruffy and itchy skin within hours and a dull coat very quickly! But it doesn't really matter whether he would do well on a different diet. He is doing incredibly well on what I feed him, just today he was racing around with a lurcher for a good few minutes at top speed (and stopped panting afterwards within a minute or so) and my vet has so far never detected any problems with his heart or any other organs (he will be 10 years old later this year)!
In addition, vegan dog foods have come a long way since the 80ies as have the supplements and the general knowledge about them. So I would suggest that a good vegan diet these days is probably a lot more balanced and nutritionally complete than it used to be thirty years ago.
And of course, chances are that the vegan diet and the heart problem in your dog were coincidence. I know a considerable amount of dogs that had/have heart problems and they are on a meat based diet. I have never come across the suggestion that vegan/vegetarian dogs are more prone to heart problems (or any other particular issues) provided a good vegan/vegetarian diet is fed and not just something home cooked that is lacking in complete nutrition.
And it is interesting - and this is not a dig at anyone (and is not in response to your post, Goldmali), just an observation - that most criticism about vegan/vegetarian diets seems to come from raw feeders, which themselves are often at the receiving end of criticism for their way of feeding. I would have thought that knowing what it is like to be feeding differently to the majority, but being confident that it is the right thing for their own dogs, might make them a bit more open minded about other owners feeding a different diet which they too are confident that it is the right thing to do! But alas, everyone seems to be very narrow minded/often fanatical about their own way of doing things and doesn't give other owners the credit to also be intelligent enough to also doing things right, albeit differently. :-( After all, dogs have survived for as long as they have because they are incredibly adaptable in so many areas, including diet.