Rosie O'Donnell's Dog Nicky Dies
10/15/2012 AT 03:05 PM EDT
Nicky, a Lab mix adopted from an animal shelter 13 years ago, died from old age.
"RIP NICKY O BOY – [our] miami born rescue dog – loyal smart nearly perfect for over a dozen years," O'Donnell, 50, Tweeted Friday.
The comedian, who recently suffered a heart attack that nearly killed her, told PEOPLE that the dog was a protective presence in her family, which includes new wife Michelle Rounds, and children Parker, 17, Chelsea, 15, Blake, 12, and Vivienne, 9.
"One day, when Blake was 2 years old we were all snow tubing on the hill and Blake jumped in the tube and it started going down," O'Donnell wrote in an e-mail. "Nicky put his paws on the tube and held it so Blake wouldn't go down alone."
O'Donnell and Rounds also share two other dogs – a 4-lb. Chihuahua and a 4 lb. Pomeranian.