There is no need for any discussion on this. From page 2, under Effect of Tokyo, the rules are quite clear:
The monster in Tokyo cannot use the [heart] result on the dice (but can heal using cards)
So house rules are only required if you want to disallow the use of cards to heal in Tokyo.
The monster in Tokyo cannot use the [heart] result on the dice (but can heal using cards)
So house rules are only required if you want to disallow the use of cards to heal in Tokyo.