I concur, venison heart is excellent and a favorite dish of mine for many many years. As a young boy, i'd kill a barley buck behind my grandparents ranch house every year on opening morning. I'd get the heart to my Grandmother as soon as possible and by the time my deer was hung, fully dressed, and halved, she'd have the heart fried up and along side some fresh ranch eggs and pancakes for my breakfast. Delicious!!
This year, some 40+ years and many animals later, for the first time i had antelope heart to try. I found it near impossible to tell from Deer heart. Try it if you think you might like it. It's not the most tender parts of a animal but i think you'll enjoy it fresh out of the animal, spiced, floured, and into the oil, butter, grease, or what have you. It's the only part of an animal i actually like somewhat over cooked.
Joey