Many people don't realize each year heart disease kills more women than men. And statistics show some treatments are not as effective in women. Now, new research may have the answer as to why.

Heart disease runs in Jill Newgent's family. At age 47 she had a heart attack.

"I went to the doctor and was actually diagnosed with indigestion," she said. "I went back several times and ended up having a stress test which confirmed I did have a heart disease."

For decades, heart disease was considered a man's disease. But the reality is -- each year heart disease kills more women than men.

According to new research, one reason for this may be an often unrecognized problem called "small vessel disease."

It's more common in women, particularly in older women, particular in diabetes, particularly smokers.

Small vessels supply blood more directly to the heart's muscle tissue.

When they don't expand properly that can cause symptoms similar to a heart attack. But it also can be much less obvious.

Diagnosing small vessel disease can be difficult, because standard tests like an angiogram used for diagnosing large vessel blockages cannot detect the problem.

Intead, MRIs, or Nuclear Tests, can be used to detect the disease.

And when it comes to treatment, traditional methods like bypass surgery and angioplasty are ineffective.

The earlier small vessel disease is detected, the better the chance of preventing heart damage.

It's advice Jill now lives by: exercising and maintaining a healthy weight.