Heart disease is the No. 1 killer of women and their doctors often underestimate the risk, because they think it's something more likely to strike men. Women aren't getting nearly the same kind of preventative care that more receive; only 36 percent of open heart surgery and 33 percent of angioplasty are performed on women.

The new guidelines are intended to right the historical gender inequity in treating heart disease, which kills 500,000 women in United States each year and millions more worldwide. Doctors find it difficult to diagnose heart disease in women because available tests are less effective for them than for men. The basic stress test, for instance, is less accurate in women because they, by nature, have more electrical abnormalities in their body system that could be misinterpreted as heart malfunction. Also, their breast tissue may be too dense to give a correct reading of cardiac activity.

The female body, meanwhile, responds differently to treatment. Aspirin therapy, a common recommendation for at-risk men to thin the blood and prevent clots, is more likely to cause bleeding and stroke in women. Aspirin is recommended for all high-risk and some intermediate -risk women but not for those at low risk. Women's hearts and arteries are smaller than men's, which makes them potentially easier to clog. For this reason they are also harder to operate on, which possibly explains the higher mortality rate among women than men for bypass surgery.

It's also important to correct any misconceptions about prevention. One recent study showed a lot of women still believed that vitamins E, C, A and aromatherapy prevent heart disease, but there is no evidence that they do. The point is people have their beliefs about their care. But preventive and therapeutic measures should be based on science, not on belief. The guidelines state clearly that vitamin supplements and hormone therapy are not recommended as prevention for women.