This is similar to other posts but slightly detailed so I'll post it: Two weeks ago the day after Xmas, I came home and my 12yo Shepherd/mix was fine. She was at least outwardly, a perfectly healthy and energetic dog for her age, and passed her yearly exam only two months earlier.
She went out and used the bathroom normally and came to the back door acting normally. Then, I saw her lay upright on the ground and start a very very slow, deep, breathing. She was not choking. She would not drink water or look directly at me. She then tried to stand and wobbled up, very unsteady, took a few steps, and her bowels emptied a large amount of stool (not watery, normal), onto the ground. She walked a few feet more, laid down, rolled over, and breathed the deep, slow, heavy breathing for 3-4 minutes, and then, she died. She did not seem to be in any apparent pain or panic/distress during the entire thing. Once she passed, she was just staring forward, and her tongue was "twisted" slightly and hanging out.
We're devastated, as this was completely unexpected and sudden. Now, on one board I saw one vet say that other vets that say it's a heart attack are "lazy", and that nothing can be even remotely concluded unless a necropsy is done - and even then maybe nothing will be known. I find it hard to believe with decades of modern veterinary medicine behind us now, that there are no semi-conclusive answers out there since this is happening to quite a few people (?). I realize without a necropsy there's no way to know 100%, but with the description I gave is it "reasonably safe" to assume this was some sort of sudden and powerful cardiac event, or, does it sound more like a stroke? Thank you