That's basically what the vet said too. In school, he was taught that hearts are weak for humans, livers for dogs, and kidneys for cats...they just plain wear out if nothing else goes wrong.
Fortunately, at least in Smokie's case it really didn't cause anything more than a little nausea and discomfort for her. She never seemed to be in any pain. She quite literally passed away from a lack of energy because she couldn't process food and all her fat reserves were eventually used up.
