Arnold Schwarzenegger is "thankful" after having open-heart surgery.

The "Terminator" star took to Twitter on Monday to give his 4.4 million followers a health update. In doing so, he also thanked the medical staff at Cedars-Sinai Hospital.
"It's true: I'm back! I went to sleep expecting to wake up with a small incision and woke up with a big one – but guess what? I woke up, and that's something to be thankful for," he tweeted on April 2. "Thank you to the doctors & nurses. And I'm truly filled with gratitude for all of the kind messages."
The former California Governor went to Cedars-Sinai Hospital on April 29 for a catheter valve replacement. During the surgery, which was called "somewhat experimental," he developed some complications.
After the surgery, Arnold's rep said, "Governor Schwarzenegger underwent a planned procedure at Cedars-Sinai to replace a pulmonic valve that was originally replaced due to a heart defect in 1997. That 1997 replacement valve was never meant to be permanent, and has outlived its expectancy, so he chose to replace it yesterday through a less-invasive catheter valve replacement."
The rep later tweeted that Arnold woke up from the procedure and his first words were, "I'm back."