Former California Governor and actor Arnold Schwarzenegger, 70, is in stable condition Friday after he had emergency open-heart surgery.

According to reports, the Terminator actor developed complications from an experimental catheter valve replacement on Thursday at the Cedars-Sinai Hospital in Los Angeles.

The Associated Press reports that Schwarzenegger had a scheduled procedure to replace a pulmonic valve on Thursday, according to spokesman Daniel Ketchell. He was in stable condition on Friday.

“His first words were actually ’I’m back,” so he is in good spirits,” Ketchell tweeted (see tweet and statement on the procedure below).

From the AP: The operation was necessary to replace a valve that had originally been installed in 1997 for a congenital heart defect. “That 1997 replacement valve was never meant to be permanent, and has outlived its life expectancy,” Ketchell said. Schwarzenegger opted for a less-invasive catheter valve replacement procedure.

An open-heart surgery team was ready during the procedure, but Ketchell said their presence wasn’t unusual in such circumstances.