by AzureiX
In the English rules that come with the game, it is stated verbatim that:"The Monster in Tokyo cannot use the Heart result on the dice to heal (but can heal using cards)."
It doesn't state that the hearts can't be used to heal status effects like poison or shrink rays.
Personally, my understanding of the Heart effect was that it was allowed to acquire points depicted on cards, heal status effects, or acquire evolution cards when in Tokyo. It just can't be used to recover hit points.