Heartbreak is an unlockable passive item added in The Binding of Isaac: Repentance.
- Grants +0.25 damage for every broken heart Isaac has.
- Immediately grants 3 broken hearts. Every otherwise fatal hit will instead add 2 more, replacing other types of hearts if necessary, and deal 40 damage to all enemies in the room.
- Once Isaac has no non-broken hearts left, he dies. Extra lives will apply at this point.
- Found Soul: The ghost gains 2 extra hits per floor and every hit they take will damage all enemies in a room as well.
- Guppy's Collar: Guppy's collar has a chance to respawn Isaac with an extra half soul heart on death, even if Isaac has already reached 12 broken hearts.
- Keeper: Keeper will lose all coin hearts and gain 3 broken hearts, resulting in immediate death without extra lives.
- The Lost / Tainted Lost: The Lost has full benefit of the item. This lets him survive 4 extra hits, each hit adding 1 damage, and the 5th is fatal.
- Plan C: Upon use no broken hearts are gained and Isaac dies.