Actor Mark Sheppard collapsed in his kitchen on Friday and suffered a cardiac emergency, he said in a Saturday post to Instagram. 

The "Supernatural" actor, who portrayed the character Crowley in dozens of episodes, said his chances of survival were "virtually nil."

"Six massive heart attacks later, and being brought back from dead 4 times I apparently had a 100% blockage in my LAD," Sheppard wrote in the caption alongside a photo of himself in a hospital bed.

Sheppard thanked his wife, the Los Angeles Fire Department and the Providence Saint Joseph Medical Center's staff. The Los Angeles Fire Department commented that they were glad to hear Sheppard was doing better. 

"They went above and beyond," Sheppard replied to the fire department. "Brought me back 3 times and delivered me safe to St. Joseph's. Beat 100 pc occlusion in the widowmaker."

A widowmaker heart attack happens when there's a blockage, also known as an occlusion, in the heart's biggest artery, according to the Cleveland Clinic. The blockage prevents blood from moving through your left anterior descending (LAD) artery. 

"Immediate treatment is crucial for a chance at survival," according to Cleveland Clinic.

Actor Misha Collins — who portrayed Castiel on "Supernatural" — wished Sheppard a speedy recovery.

"Mark! You don't need to do the most and biggest every time! 6 heart attacks? 2 or 3 would have been impressive enough," Collins wrote. "You've impressed us, okay. Now stop with this heal up and get back on the road with us. Love you, pal."

Just weeks ago, Sheppard wrote on Instagram that he'd lost nearly 40 pounds. 

"Never felt better," he wrote. "New era."

Aliza Chasan

Aliza Chasan is a digital producer at 60 Minutes and CBSNews.com. She has previously written for outlets including PIX11 News, The New York Daily News, Inside Edition and DNAinfo. Aliza covers trending news, often focusing on crime and politics.

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