Although heart disease is the No.1 killer of women in this country, signs of a heart attack are often overlooked by women aged 55 and younger, according to the results of a new study.

Researchers at Yale University Medical Center in New Haven, Conn. studied 30 women (average age 48) who had suffered a heart attack. And while heart disease is more common in women after menopause — the study proved younger women are still very vulnerable.

“Young women represent less than 5 percent of all patients with heart disease. This is significant because it still translates to 16,000 deaths and about 40,000 hospitalizations annually," said Dr. Judith Lichtman, lead author of the study and associate professor of epidemiology and public health at the Yale School of Medicine, in a news release.

Lichtman and her colleagues interviewed all 30 women within seven days of their release from the hospital. The in-depth conversations touched on everything from initial symptoms to why the women didn't seek immediate medical attention.

"We found that most failed to connect their symptoms with a heart condition, commonly misattributing them to fatigue, indigestion, stress or overexertion,” said Lichtman.

“We learned that many of these women had no idea that they were at risk for heart disease and were unaware that their symptoms could be connected with a heart problem, citing the lack of good examples in the public media to help them recognize atypical symptoms, or realize that someone their age could even be at risk for a heart problem," she added.

Dr. Louis Evan Teichholz, chief of cardiology at Hackensack University Medical Center in New Jersey told FOXNews.com he is not surprised by these findings at all.

"We know that women who have heart attacks can have very atypical symptoms — not the same as men," he said.

Men are more likely, from many studies, to have classic heart attack symptoms such as:

— Severe crushing chest pains

— Feelings of doom

— Sweating

— Pain down the left arm

"When people have those kinds of symptoms they are more likely to believe they are having a heart attack and more likely to get to the emergency room," Teichholz said.

"But what we found in many studies with women is that they're more likely to be atypical symptoms and therefore they are less likely to seek medical attention."

Atypical Symptoms include:

— Abdominal discomfort/indigestion

— Nausea

— Fatigue

— Shortness of breath

"If these symptoms persist and there are no other explanations," Teichholz said. "I would start to think about calling 911."

According to the American Heart Association, heart disease claims more than 460,000 women's lives every year — that's about one death per minute.

Researchers presented their findings May 1 at the American Heart Association's 9th Scientific Forum on Quality Care and Outcomes Research (QCOR) in Cardiovascular Disease and Stroke.

Click here to read more about this study.