Heartbeat is a Rare Fortnite Wrap. This cosmetic has been leaked, and the wrap will hopefully be available to purchase in the near future! Heartbeat was first added to the game in Fortnite Chapter 2 Season 5.
How-to Get the Heartbeat Wrap
Heartbeat was leaked or datamined, which means we don't know for sure how it will be released. Most cosmetics that are leaked will be released within 30 - 60 days of their discovery.