The study said heart disease can sneak up on women in ways that standard cardiac tests can miss.
It also said women tend to have different symptoms than men. Women are more likely to die in the year after a first heart attack.
Many heart-related studies still don't focus enough on women, researchers said. Only a third of studies include information on how each gender responds to treatment.
More than 40 percent of women still don't realize that heart disease is the No. 1 female killer. One in 30 women's deaths in 2007 was from breast cancer, compared to about 1 in 3 from cardiovascular disease, according to the American Heart Association.
The Associated Press contributed to this report.