In a recent video shared on YouTube, Schwarzenegger said the operation took place several years ago, just before he started working on Terminator: Dark Fate (released in 2019).
Schwarzenegger remembered waking up after the procedure and seeing his doctor, who told him the operation had not gone as planned. The actor said the procedure was supposed to be a relatively non-invasive one to replace a heart valve, but his doctors “made a mistake and poked through the heart wall.”
https://youtu.be/F-vTVjV-2×8