By the time he was laid on the table he had stopped breathing and couldn't be revived. I just would like to know more about heart failures in cats and how to watch for signs or symptoms, or if this sort of thing is common, or if it could have been caused by something that was dormant in him from being a stray cat. I'm sorry over your loss. Cardiomyopathy is a terrible disease. We do see heart problems from amino acid deficiency.
Canine parvovirus can affect a dog's heart.
There was nothing you should have done differently, and you shouldn't run into this problem again. I got her at the spca 7 yrs. She had black crusts then around the inside corners of her eyes, but the vet didn't comment and gave her a clean bill of health. 2 yrs ago she developed black crusts around her nostrils, with a fever and lethargy. She had a general and then a geriatric blood panel which showed no outstanding abnormalities.