Charlie, I had never heard of a "heart dog" either until I read the book and it described me and my Boo perfectly. He was my heart and I was his. We had a bond that existed and not many humans believe possible with an animal. I will never stop missing my "baby booter", my "ole man boot". He had lots of nicknames. 😉 When he passed away in my car I was singing to him.
Deepblue: you are in the right place here. People understand the connection.
Peace to everyone this weekend.
Boo' s mommy