Your heart has been replaced with advanced technologies: You cannot be poisoned, and filters in your heart will also regulate bleeding and healing, allowing all healing items (chems) to function at a higher level. Robots are now confused by you and 50% less likely to score a critical hit.”— Fallout: New Vegas description
In the initial dialogue with Dr. Klein as part of the quest Welcome to the Big Empty, the Courier finds out that their brain, heart, and spine have been removed and replaced. This perk represents the replacement of their heart. While technically having these perks from the start of the add-on, they are unlocked in the course of the conversation.
Immunity to poisoning, adds a +25% bonus to healing items and -50% to Critical Chance for robots against you.
- Since the Cloud in the Sierra Madre is not poisonous but highly corrosive, it will still hurt the Courier even with this perk.
- Heartless shares the same Vault Boy image as Cardiac Arrest.
- Both Cardiac arrest and Heartless do not affect healing from any items as they are missing the correct modifiers.