University of California - Davis researchers also found that two specific electrocardiogram (EKG) indicators of heart stress during an Exercise treadmill test (ETT) further enhanced its predictive power.
The study can help guide cardiologists in making the treadmill test - an accessible, economic and easy-to-administer evaluation of patients with heart disease symptoms - more useful in clinical practice.
"Newer cardiac imaging technologies are more accurate in identifying the presence of heart disease, but those tests are considerably more expensive than ETT and in many cases unnecessary" said Ezra Amsterdam, senior author of the study.
"Our study found that the test is a very valuable tool for identifying coronary artery disease in women older than 65, and that it can be used to help select those who may require higher-tech diagnostics," Amsterdam said in a statement.
During ETT, a patient exercises on a treadmill at gradually increasing speed and elevation while undergoing blood pressure monitoring and an EKG to gauge exercise-induced changes in the heart's electrical activity.
If signs of heart disease are present, more definitive and invasive evaluations such as coronary angiography may be conducted to determine if any blood vessels are narrowed or blocked by plaque.
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Coronary angiography, which produces a series of X-rays of the interior of the arteries by injecting dye into them to make them visible, may be recommended when there is evidence of heart disease.
The current study analysed 111 women who had seen their doctors at UC Davis Medical Center because of chest pain and whose exercise treadmill tests were "positive," indicating they should have further cardiovascular testing.
Coronary angiography was performed on each patient, and the researchers analysed how often the results showed definite evidence of arterial narrowing.
They found that overall only half of the women with positive treadmill tests had coronary artery disease as determined by coronary angiography. But when test results were evaluated by age, the predictive value of ETT rose.
The study was published The American Journal of Cardiology.