Donna, I'm so sorry for your loss. I had two dogs who had fatal heart attacks and I know the cry that they make. It's an awful sound and one that is still w/me to this day. Nothing I can say will make you feel better right now b/c you know that MooShoo is no longer in pain and is free but that doesn't fill your empty arms at night. As you know from having lost other cats through the years, the pain will lessen and you'll be left w/only good memories. Take heart; MooShoo knows how loved he was and still is. RIP, dear MooShoo and peace to you, Donna.