Amy Yasbeck has gone back over the worst night of her life in fresh detail, telling Fox News Digital that her husband John Ritter was treated for the wrong condition in the hours before he died in September 2003.

Ritter, known to a generation as Jack Tripper on Three's Company, collapsed on the set of 8 Simple Rules...for Dating My Teenage Daughter. He'd complained of feeling sick to his stomach, told the show's director James Widdoes as much, then went to lie down in his dressing room. What followed was sweating, vomiting and chest pain, and the studio doctor called for an ambulance.

At Providence St. Joseph Medical Center, doctors assumed a heart attack. Yasbeck says that assumption is what went wrong.

"And they didn't do any imaging, but he looked like the guy — right age, right weight, everything, to have a heart attack, and he had chest pain. So they just started loading him up with blood thinners and stuff," she said.

The actual problem was an acute aortic dissection, a tear in the inner wall of the body's largest artery. Treating it like a blocked heart vessel, Yasbeck says, made things worse rather than better.

"It wasn't a block in his heart, it was a tear in his aorta, so everything they did that night led to what eventually happened," she said. "Because there are ways, once it starts dissecting, if you get to the hospital in time, your chances are way better of living."

Ritter spent four hours in the emergency room before he died. He was 54.

A lawsuit, a foundation, and a phrase doctors now use

Yasbeck later filed a wrongful death suit alleging the dissection had been misdiagnosed. A jury eventually sided with the two physicians who remained defendants in the case. What she built afterward has outlasted the courtroom outcome. Yasbeck founded the John Ritter Foundation for Aortic Health, which pushes for better awareness, detection and treatment of thoracic aortic aneurysms and dissections.

She told Fox News Digital that her husband's case has quietly become shorthand in emergency rooms. Once, taking a friend in with chest pain, she was told the friend would need a CT scan to rule out "the John Ritter thing". Hospital staff who had no idea they were talking to his widow.

The interview, which also featured the couple's son Tyler Ritter, ran on September 17, what would have been John Ritter's 78th birthday. More than two decades on, Yasbeck's foundation is still lobbying for the imaging protocols that, by her account, might have changed what happened that night in 2003.