Narrator: This is Science Today. Women die of heart disease five times more than they do of breast cancer. Yet Barbara Drew, an associate professor at the University of California, San Francisco's School of Nursing, says there's still a perception that heart disease is a man's disease.

Drew: However it is the number one killer in women and women of all ethnic groups. And women have poorer outcomes from heart disease than men do. They have poorer outcomes after cardiac surgery and after most procedures.

Narrator: Drew says there are many theories why that is.

Drew: Women tend to be older by the time they develop heart disease and that may have something to do with it. They may have smaller coronary arteries which are harder to work with and women have been noted to have atypical chest pain symptoms sometimes, which cloud what is wrong with the person and make diagnosis more difficult.

Narrator: It's estimated one out of nine women aged 45-64 will develop heart disease and after 65, one out of three. For Science Today, I'm Larissa Branin.