The troponin I test was better than 90 percent sensitive in detecting heart damage and 90 percent specific in determining whether it was due to a heart attack, the study found.
A second study led by Swiss cardiologists reported on the use of newer tests for both troponin I and troponin T on 718 people who came to emergency rooms with symptoms indicating possible heart attacks.
"The diagnostic performance of sensitive cardiac troponin assays is excellent, and these assays can substantially improve the early diagnosis of acute myocardial infarction [heart attack], particularly in patients with a recent onset of chest pain," the researchers wrote.
The choice of a troponin test still might not be easy, Ohman said. For example, he prefers a test for troponin T. That is a minority choice in the United States, where about 60 percent of physicians test for troponin I, Ohman said.
More studies probably are needed to help doctors make a choice, he said. "We need to assay the sensitivity of tests in a broader range of patients," he said of the European studies. "I suspect that they had many more patients and somehow selected out the more likely cardiac patients. We need to do many more studies on patients with a lower chance of cardiac disease."
The increased sensitivity of the newer tests might pose a problem in some cases, Ohman said. "Once you are able to detect smaller and smaller infarcts [damaged heart areas], you can be detecting damage that may not be a clinical heart attack," he said, which would complicate the choice of treatment.
Increased troponin levels can be due to "a whole host of conditions" other than a heart attack, including inflammation from myocarditis and even strain on the heart from blood clots in the lung, Ohman said.
The increased sensitivity of the newer tests might raise some issues, but the two studies "should provide an increas
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