Artificial heart

An artificial heart is a device used to replace a heart.

In the 2320s, Jean-Luc Picard had to have a artificial heart replace his original after being stabbed by Nausicaans. 

In 2365, Picard had to have it replaced after it malfunctioned. 

In 2374, Julian Bashir replaced Ishka's heart with an artificial replacement. 

In 2377, Kira Nerys' heart was damaged after being attacked by Taran'atar, forcing Bashir to replace it.