It’s been 15 years since John Ritter suddenly died at the age of 54. A seemingly healthy man passed away from what doctors believed to be a heart attack, but that wasn’t the case at all.

Ritter didn’t die from a heart attack it turns out. Instead, he had been living with an undiagnosed aortic dissection. When the symptoms first appeared, Ritter went to the hospital complaining of not feeling well. He was given blood thinners, which should never have been prescribed to a person with his condition. He died that evening on set. He is one of 15,000 people in the U.S. who die annually of the disease.

It is often called the silent killer and results when the inner layer of the aorta tears. The symptoms often mimic other illnesses, but are treatable if diagnosed early on. The risk of dying from the disease rises one percent every hour, making it important to catch it as early as possible. Some of the symptoms include sharp pain in the chest, neck, back, or stomach.

Ritter’s wife, Amy Yasbeck, is determined to not let her husband’s death go in vain and is taking steps to bring awareness to the disease. She wants people to know the signs to look for as well as the treatments and diagnostic tools.

To detect the condition, doctors need to perform a CT Scan, MRI, or Transesophageal echocardiogram rather than an x-ray or EKG. Had John’s doctors done one of those tests, he might still be with us.

Amy even started a foundation called the John Ritter Foundation that works to raise money for research for the condition and educate people about aortic dissection.

The foundation teamed up with the Thoracic Aortic Disease Coalition and created a set of rules called Ritter Rules to help people recognize the signs of aortic dissection.

She says these rules were not around when John passed away, but were published in 2010 by the group that she is involved with. They help recognize the symptoms of the condition and how to treat it.

Amy says that people need to understand that family history plays a role in aortic dissection because it often runs in families. Other causes can include poorly managed blood pressure, injuries to the chest, and drug use.

Check out the video below to learn more about Amy and the John Ritter Foundation and be sure to share this story with your family and friends. It might save someone’s life.