WEDNESDAY, March 7, 2007 (HealthDay News) -- Even minor abnormalities in electrocardiogram readings can predict if a seemingly healthy, postmenopausal woman is at risk of a heart attack or even death, a new study found.
"In terms of predicting heart disease outcomes, EKG (electrocardiogram) is giving additional information that isn't available" from the usual heart disease risk factors, such as high blood pressure, elevated cholesterol or increased blood sugar, said the study's lead author, Dr. Pablo Denes, a professor of medicine at Northwestern University's Feinberg School of Medicine.
An electrocardiogram is a non-invasive test that measures the heart's electrical activity. It's sometimes referred to as an EKG or an ECG, and can be performed in a doctor's office.
While the test has been studied in men as well as in women who already have heart disease, Denes said the test hadn't been well studied in healthy women.
The new study is published in the March 7 issue of the Journal of the American Medical Association.
To learn if the test was effective at predicting heart disease risk in healthy women, Denes and his colleagues gathered data from the Women's Health Initiative, a large U.S. trial started in 1991 to address the most common causes of death and disability in postmenopausal women. The study authors focused on data involving women in the hormone replacement therapy section of the trial. Women were enrolled in the study beginning in 1993 through 1998. The WHI was stopped in 2002, after it became clear that hormone therapy increased a woman's risk of heart attack, stroke and breast cancer.
The new study included almost 15,000 women between the ages of 50 and 79. All had EKGs done at the start of the study, three years later, and again six years later, if they were still participating in the trial. The average follow-up time for the study was 5.2 years.
Most women -- 9,744 -- had normal EKGs at the start of the study. Another 4,095 women had minor abnormalities in their EKG reading, while 910 had major abnormalities. One hundred and eighteen women who had normal EKGs went on to have a coronary heart disease event, such as a heart attack or death due to heart disease. Ninety-one women who had minor abnormalities eventually had a heart disease event, and 37 women with major abnormalities had such an event, according to the study.
The researchers found that women who had minor abnormalities had a 55 percent increased risk of a coronary heart disease event, while women with major EKG abnormalities faced triple the average risk of such an event.
About 5 percent of the women who had normal baseline EKGs developed abnormalities during the study period. These women had a 2.6 times higher risk of a coronary heart disease event.
Whether or not a woman was taking hormones had no effect on an EKG's ability to predict heart trouble, according to the study.
"This is a test that predicts the future," said Denes. "Hopefully, it can inspire people who are having a hard time deciding to lose weight, increase their physical activity or eat a healthy diet, because now they know there's an additional factor that suggests you'll have trouble in the future."
Denes did offer one caveat to the findings, however. He said because the study population was mostly white, the researchers don't know if the test will be as useful in predicting heart disease risk in minority women.
Dr. Nieca Goldberg, medical director of New York University's Women's Heart Program, said, "This is really an untapped field that has never really been looked into, and it looks like electrocardiograms are more predictive than we thought."
Goldberg recommends that women should have a baseline ECG at age 50, and women of any age who have heart disease symptoms should also have the test.
"If the ECG is abnormal, that should trigger a more aggressive evaluation for heart disease," she said.
To learn more about electrocardiograms, visit the American Heart Association.