DALLAS, Nov. 17 -- An imaging technique employing single-photon emission computed tomography (SPECT) can predict the risk of a second heart attack or death among coronary patients better and sooner than the widely used exercise stress test, asserts a report in the American Heart Association's journal Circulation. According to lead author Kenneth A. Brown, director of the University of Vermont's nuclear cardiology and cardiac stress laboratories, the technique -- known as vasodilator perfusion imaging -- can be used as early as two to four days after a heart attack with no complications, allowing treatment decisions to be made quickly and potentially preventing further heart attacks.
The study compared two groups totaling 451 patients. One group of patients had the new imaging test administered two to four days after suffering initial heart attacks, with the exercise stress test following six to 12 days later; a control group of patients was given the exercise stress test alone. The patients who underwent vasodilator perfusion imaging were first given a drug called dipyridamole, which increased blood flow through the heart by dilating blood vessels while the patients were lying down. The patients were then given a dosage of a mildly radioactive drug to provide images of blood flow. Brown and his colleagues found that the imaging technique could be administered earlier than standard exercise testing, and better identified patients at greatest risk of future heart attacks.