Haptic Heartbeat

Haptic Heartbeat can help reduce your heart rate if you're feeling anxious or having a panic attack.
First, you input your current heart rate and a target heart rate.
Then, the app simulates a heartbeat that syncs up with your own. Your brain will begin to externalize your heartbeat and sync it up with the virtual one!
Finally, the app simply slows down the simulated heart beat, which can help slow down your real heart rate!
You can also enter "Steady Heartbeat" mode for a simple controllable heartbeat.