Leveling up isn't the only way to get stronger Path of Exile 2. Getting better items is arguably more important than getting a few extra levels, but if you really need to get a new passive or two, then there are plenty of things in the game that can give you extra points. The Sacrificial Heart is one such item.
The sacrificial heart is one of many permanents PoE 2 the campaign bonuses players can earn. It's a quick way to extra power, but like a lot of things in this game, figuring out what to do with it can be a little confusing.

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What to do with the Sacrificial Heart in PoE 2
The Sacrificial Heart is a usable quest item that players can use in a ritual to earn some free passive points. To do this, you must travel to Aggrat in Act 3. This is the penultimate area that only becomes available once players activate the portal in the Ziggurat camp.
Once you reach Aggorat, you must fight your way through hordes of Vaal fighters and search for a large, stone shrine guarded by an elite monster and his minions. As usual, there will be a checkpoint near this area to help you find it. After getting rid of the enemies, pick up the nearby Sacrificial Dagger and place the heart on the altar. Interact with her and your character will open her heart, giving you extra skill points in the process.
Where to find the sacrificial heart
If you're wondering where to get the Sacrificial Heart, it's a random drop from enemies in 400 BiC Utzaal and Aggorat, just like the relics for the Ancient Covenant quest in PoE 2. It may take some time before you can get it, but once you do, go straight to the location mentioned above to use it. Note that empty instances reset every 8-15 minutes. Once you've found the stone shrine, try not to leave that instance of the map for too long, or you'll be forced to find it again.
Entering Aggorat in cruel difficulty
Once you beat the Act 3 boss, the return portal from 400 BiC to Camp Ziggurat will automatically send you back to the start of Act 1 (but on cruel difficulty). To use Sacrificial Heart without fighting to Act 3 Crude, go to a waypoint and teleport back to Aggrat in Act 3 Normal.