Sheppard, who starred in the series "Supernatural," collapsed in his kitchen.
He posted on Instagram a picture of him lying in a hospital bed at Providence Saint Joseph Medical Center in Burbank.
The 59-year-old says he survived six heart attacks and was brought back from the dead four times after a complete blockage in his artery.
Sheppard says if it wasn't for his wife, the Los Angeles Fire Department, and the hospital, he wouldn't be alive.