John Ritter’s family warns about the hidden but treatable heart condition that killed him — on what would have been his 78th birthday

For generations, something troubling seemed to plague the men in John Ritter’s bloodline.

“We always heard, ‘Oh those Ritters die of their first and last heart attack,’ ” Amy Yasbeck, the beloved comedian’s widow, told The Post. “[John’s dad] clutched his chest and fell over. He was 60-something years old.”

Country music star Tex Ritter’s sudden death was blamed on a cardiac emergency. Decades later, doctors made a similar assumption when his son showed up at a Burbank hospital sweating profusely, vomiting and complaining of chest pain in September 2003.

But John wasn’t having a heart attack — and his family now suspects his father didn’t either.

In reality, the “Three’s Company” star was suffering from an aortic dissection, a medical emergency involving the body’s largest artery that doctors initially failed to recognize before it claimed his life at 54.

“The sad truth of the matter is that because it’s so much more common for it to be a heart thing, John was treated for a heart attack before they had done any imaging, and that exacerbated it,” Amy, 64, said. “This happens way too often.”

Now, on what would have been John’s 78th birthday, his loved ones are sounding the alarm about aortic disease — and urging people to know their family history before tragedy strikes.

“We’re just ringing the alarm,” said Tyler Ritter, John’s second son and third child with ex-wife Nancy Morgan. “If we can catch it ahead of time, we can prevent it.”

A hidden killer

An aortic dissection occurs when the wall of the aorta, the body’s main artery, tears. Blood can then force its way between the artery’s layers, potentially cutting off blood flow to vital organs including the brain, kidneys and heart, according to UChicago Medicine.

“Time is of the freaking essence when this happens,” Amy said. “Fifty percent of people don’t even make it to the hospital.”

In July, Sen. Lindsey Graham died unexpectedly at 71 after an aortic dissection. Depeche Mode’s Andy Fletcher, “Rent” playwright Jonathan Larson and “Growing Pains” star Alan Thicke are among the other celebrities whose lives were cut short by the condition.

In Ritter’s case, doctors initially suspected a heart attack and treated him accordingly. When his symptoms worsened, a second test appeared to confirm their diagnosis, so they administered blood thinners and performed a cardiac catheterization to examine his heart.

It was during that procedure that doctors discovered the real emergency: a massive aortic dissection.

According to a wrongful death lawsuit filed by Ritter’s family, blood thinners and catheterization were the “exact opposite” of what Ritter needed. He required emergency surgery to repair the tear, and the lawsuit argued that a chest X-ray could have revealed his enlarged aorta and pointed doctors toward the potentially lifesaving operation, People reported.

Both of Ritter’s doctors were ultimately cleared of wrongdoing. His children and Amy received settlements in other suits, including those involving the hospital where he was treated.

“Raise your suspicion of this. Maybe your family didn’t all fall off their tractors and die. Maybe they died first and then fell off their tractors.”

Amy Yasbeck

The family clues that could save your life

While aortic dissections can be deadly, the John Ritter Foundation estimates that up to 80% of patients could survive if the condition is diagnosed and treated quickly.

The first step is simple: Find out your family history.

The same inherited gene mutations that can cause an aortic dissection can also trigger an aneurysm — a dangerous bulge or weakening in the aorta’s wall that can eventually tear. They often have no symptoms.

Other inherited conditions, including Marfan syndrome, Loeys-Dietz syndrome and bicuspid aortic valve disease, can also weaken the aorta and run in families.

In fact, as many as one in five people with a thoracic aortic aneurysm or dissection have a relative with the same condition.

Researchers have found hundreds of genetic variants across 11 genes linked to aortic disease, and they’re still looking for more.

Genetic testing can check for many of these known mutations, and the results can help doctors decide which medications might be helpful, how often someone should get scans and whether preventive surgery is needed. It can also help identify family members who may be at risk.

“Raise your suspicion of this,” Yasbeck said. “Maybe your family didn’t all fall off their tractors and die. Maybe they died first and then fell off their tractors.”

Regular imaging of the aorta can also help catch problems like an aneurysm early — giving doctors a chance to intervene before it leads to a potentially deadly dissection.

“People who know their story or suspect a misdiagnosis in their family or know someone they’re related to that’s had a dissection, those are the people we want going in right this second,” Tyler, 41, said.

John’s brother was saved by a scan — and his kids are getting screened, too

The Ritters have taken their own advice to heart. After their father’s death, each of his four children began getting annual scans to keep tabs on their aortic health.

Other relatives have, too. Just four years after John’s death, his older brother Tom had lifesaving surgery to replace and repair part of his aorta after imaging tests detected a previously unknown aneurysm.

The surgery, Tyler said, gave his uncle “a full new lease on life” — and showed the family just how important it is to know your risk and stay on top of your health.

“Part of our foundation is teaching people how to be [their own] advocate,” the actor said.

That’s especially important with aortic dissections, which are considered relatively rare. About 20,000 cases are documented in the US each year, but Yasbeck said the real number may be considerably higher because many likely go undiagnosed or are attributed to other things.

That’s why, Tyler said, it’s important to have a doctor you trust and to speak up if you feel like something is being overlooked.

“If you sense — and I’ve had this personal experience — that your doctor or cardiologist is putting you down or saying you don’t know what you’re talking about, maybe find another doctor,” he urged. “You want to find your right fit.”

After all, family history isn’t the only thing that can raise the risk. Chronic, uncontrolled high blood pressure, stimulant or illicit drug use and chest trauma can also increase the odds of an aneurysm or aortic dissection.

Remember STAT

The John Ritter Foundation recommends memorizing a simple acronym that could help you — or someone else — survive an aortic dissection: STAT.

• S — Suspect: Watch for warning signs, including sudden, severe “tearing” or “ripping” pain in the chest, back, neck or abdomen. Numbness or weakness in an arm or leg can also be a red flag.
• T — Time: Don’t wait it out. Get to a hospital with advanced cardiac surgery capabilities as quickly as possible.
• A — Aortic imaging: “CAT scan is the gold standard in the emergency room,” Yasbeck said.
• T — Talk: Share your family history with your relatives. Knowing their risk may help them get appropriate screening and monitoring. Talking with your doctor can also help them spot a dissection more quickly.

If you know you’re at risk for an aortic aneurysm or dissection, Yasbeck also recommends carrying a card in your wallet with your diagnosis and family history. You can also keep the information in a medical profile on your phone.

“It’s important that you’re treated for the right thing,” she said. “Our whole thing at the foundation is to be able to … aid in a world where people can avoid the suffering our family went through — and it’s working. But the fight continues.”