The FDA has said that grain free dog food can be linked to heart problems in dogs because dogs do need some grain in their diets to promote healthy hearts.
But eating the grain free dog food isn't likely the cause of the heart disease or heart problems in the dog but having a grain free dog food diet constantly could cause your dog to have more of a risk of developing heart disease and heart problems.
But the grain free dog food isn't the exact cause and as long as you feed your dog some grain based dog food he or she should stay healthy and avoid heart problems.
It's also a good idea to keep your dog up on it's heart worm medicines as well and have regular vet checkups to catch any heart problems or any other heart issues or health issues early on.