Cavolo! you ran out of hearts
Cavolo is a common exclamation; yes, it means cabbage, but it's an euphemism for a similar, and more vulgar, exclamation, similar to how an English speaker would say "darn" or "gosh". Another variant is "caspita".
I'd suggest a milder exclamation like "accidenti" or "mannaggia"; although both of them are euphemisms for wishing bad things to happen to someone. There isn't such a thing as an innocent exclamation of disappointment :P