John Ritter's widow Amy Yasbeck details the fatal misdiagnosis she says led to his death

John Ritter's widow Amy Yasbeck is opening up about the actor's final hours more than two decades after his death. In September 2003, Ritter died at the age of 54 after suffering an acute aortic dissection, a tear in the inner layer of the aorta, the body's largest artery that delivers blood away from the heart. Ahead of Aortic Dissection Awareness Week and what would have been Ritter's 78th birthday on Sept. 17, Yasbeck, who founded the John Ritter Foundation for Aortic Health, and the actor's son, Tyler Ritter, who serves on its board, joined Fox News Digital for an interview. CARLY PEARCE SAYS HEART CONDITION LEFT HER FEARING A HEART ATTACK: ‘IS MY HEART OK?’ Looking back on her husband's death, Yasbeck recalled how Ritter was mistakenly treated for a heart attack after arriving at the hospital, which she said "led to what eventually happened." "John was sadly misdiagnosed on the night he passed away," Yasbeck said. "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," she continued. "So they just started loading him up with blood thinners and stuff." "And this is sad because it was the opposite. 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," Yasbeck said. "Because there are ways, once it starts dissecting, if you get to the hospital in time, your chances are way better of living." Following Ritter's death, Yasbeck filed a wrongful death lawsuit alleging Ritter's aortic dissection was misdiagnosed. In 2008, a jury found in favor of the two physicians remaining in the case. WATCH: JOHN RITTER'S DEATH HIT SO HARD BECAUSE ‘YOU FELT LIKE YOU KNEW HIM’: FOUNDATION CEO To mark Aortic Dissection Awareness Week, which runs from Sept. 13 to 19, the John Ritter Foundation for Aortic Health, is launching its "50 for 50" campaign, encouraging supporters to donate $50 while drawing attention to the fact that up to 50% of people who suffer an aortic dissection die before reaching medical care. Yasbeck told Fox News Digital that she believes annual estimates of aortic dissections likely undercount the number of cases because patients who die before arriving at a hospital often are not included in the data. She said that improving awareness of the condition is one of the most effective ways to reduce those deaths. However, Yasbeck emphasized that raising awareness is not just for patients and families. She pointed out the importance of ensuring doctors recognize that chest pain can signal an aortic dissection, not just a heart attack. COUNTRY STAR ASHLEY COOKE SPEAKS OUT ABOUT RARE HEART CONDITION THAT COULD END HER LIFE AT ANY MOMENT "Your heart can be in perfect shape," she said. "You can be an athlete." "And if the blood that's being pumped into your aorta is going inside the layers of the aorta, instead of being traveled to all of the rest of the highway where it's supposed to go, it's curtains for you," she continued. "So it's so important to be able to have that awareness," Yasbeck added. "And there's no drug for aortic dissection at this point in time. For blood pressure, which sometimes can help you if you are at risk, right? Keep your blood pressure down, but there's no instant fix for it. You have to be a participant in your own health in this regard. And by doing that, you are also protecting your family. For generations, actually." Yasbeck said she recently witnessed firsthand how her husband's story has become part of emergency medicine. She recalled accompanying a friend with chest pain to the hospital where medical staff told her they were ordering a CT scan to check for "the John Ritter thing" to rule out an aortic dissection. "They said, 'We're checking for the John Ritter thing', not knowing who I am, not knowing whom my friend is that was a friend of John's," she remembered. "It was just like this relief came over me. And my buddy, you know, gave me the thumbs up." "The fact that they said checking for that ‘John Ritter thing,’ talking shorthand to me, I freaking love that. Call it whatever you want. CT scan, a CAT scan, is the gold standard for diagnosing in an emergency situation, in any situation, but to be able to realize as soon as you can, ‘This is not a heart attack. This is an aortic dissection,’" she continued. "'Fix this a whole different way.'" 'GAME OF THRONES' STAR EMILIA CLARKE WAS CONVINCED SHE 'CHEATED DEATH' AFTER SURVIVING TWO BRAIN ANEURYSMS While speaking with Fox News Digital, Yasbeck shared that doctors and researchers had told her for years that Ritter's death marked a turning point in awareness of aortic dissection. "There was kind of a pre-John Ritter awareness of aortic dissection and a post," she said. "Sadly, John died in the last hours of pre-John Ritter awareness." WATCH: JOHN RITTER'S LEGACY IS HELPING PREVENT DEADY AORTIC DISSECTIONS, DOCTOR SAYS Since Ritter's death, the "Three's Company" star's family has worked through the John Ritter Foundation for Aortic Health to raise awareness about thoracic aortic aneurysms and dissections. A thoracic aortic aneurysm is an enlargement of the body's main artery that can often be detected through screening before it tears into an aortic dissection, a life-threatening emergency. Ritter's widow and his children have encouraged people to learn about their family medical history and seek appropriate screening when they are at increased risk because thoracic aortic aneurysms and dissections can have a genetic component. LIKE WHAT YOU'RE READING? CLICK HERE FOR MORE ENTERTAINMENT NEWS Yasbeck said doctors now believe Ritter's father likely died from an undiagnosed aortic dissection, while routine screenings after his death revealed the same condition in his brother Tom, allowing him to undergo life-saving surgery before it became fatal. PUT YOUR ENTERTAINMENT KNOWLEDGE TO THE TEST AND SEE HOW YOU SCORE Tyler, 41, told Fox News Digital that becoming aware of his family history in the aftermath of his father's death had changed his approach to his own health. Ritter shared Tyler as well as son Jason Ritter, 46, and daughter Carly Ritter, 44, with his first wife, actress Nancy Morgan. Yasbeck, who was Ritter's second wife, shared son Noah Ritter, 28. "It's impossible not to imagine that there's a parallel universe where the family demanded an autopsy on our grandfather and discovered an aortic dissection, which led to my dad and his brother getting screened," Tyler said. "And as we see with Tommy, as Amy just said, Tommy is still alive and doing great." "It's just too easy to imagine that in this other universe, where my grandfather was properly diagnosed, that my dad would be totally fine right now with just an aortic replacement surgery," he continued. "And that, on the one hand, is very difficult to accept and to comprehend." GET ENTERTAINMENT SCOOP DELIVERED RIGHT TO YOUR EMAIL BY CLICKING HERE "On the other hand, it has provided a massive silver lining," Tyler added. "I get scanned every year. My kids know I get scanned. They know why I get scanned. They know that my dad was the last one in our family. Our mission is that he is the last in our family to suffer a dissection." Tyler said watching his own children discover their grandfather through episodes of "Three's Company" has reinforced the importance of preserving Ritter's legacy through awareness. He explained that though aneurysms are often asymptomatic, they can be detected through screening, which is why he encourages families with a history of aortic disease or unexplained early deaths to speak with their doctors. WATCH: JOHN RITTER FOUNDATION CEO RECALLS SURVIVING LIFE-THREATENING AORTIC DISSECTION "The more you know," he said. "If you can spot in a first-degree relative that there's a potential for a missed or undiagnosed illness or disease, it would just be worth asking your doctor." Looking back, Tyler said his father's death remains a tragedy, but one that has helped protect other families. CLICK HERE TO DOWNLOAD THE FOX NEWS APP "It is unfortunate. It's a tragedy," he said. "But it has happened. And as a result, there are just countless numbers of lives that have been saved."