An estimated 25,000 people die each year from heart valve disease, but many aren’t aware of it.

Dennis Dobkowski needed surgery to fix damage to his valves. He shared his story and concerns for the problem to Congressional representatives on Feb. 22, according to a statement.

In a survey conducted by the Alliance for Aging Research, 40 percent of 2,000 respondents in the U.S. knew nothing about heart valve disease. Only about one in four knew information about it.

In a follow-up survey, results showed that out of 400 people with heart valve disease, six in 10 respondents were diagnosed only because they saw a physician for a regular check-up or some other issue.

“It’s important to have a dialogue about your heart with your health provider, no matter what your age,” said Sue Peschin, the president and CEO of the Alliance for Aging Research, in a statement. “A simple check with a stethoscope can identify a heart murmur and that can save your life.”

Many patients can have it and not even know because the disease doesn’t always present symptoms. Aortic stenosis, which rarely presents symptoms, can be deadly if left untreated.

If symptoms do arise, they can include fatigue, chest pain, palpitations, shortness of break or swollen ankles.

“Many people mistake many of the symptoms for age, or weight-related issues and don’t get them checked out, but it’s important to talk with your doctor and make sure it isn’t something more serious,” Dobkowski said.

Now that his valves have been fixed, he said he is doing much better and is able to walk three miles a day.

“At times it felt like I’d never get over the hump, but I’m feeling really good now,” he said. “I have a lot more stamina and a lot more energy.”