How to make revive item

An item that revives the player even if it does not revive the player but before the player dies like has 1 or 0.5 It heals him to 20 hearts and then the totem animation to the item and plays the totem sound with the particle (I can do the particle) with a cooldown of 10 minutes. And I want it to check if the item is in the main hand and if the player has reached 1 or 0.5 hearts and then it will trigger but it is not working