The finding could help physicians distinguish angina, a sign of coronary artery disease and possible indicator of heart attack, from other types of chest pain, such as heartburn, researchers report.

Scientists at four U.S. medical centers used a nuclear imaging technique, the SPECT scan, to test an experimental radioactive tracer called iodofiltic acid I 123 (trade name Zemiva). Studying 32 patients, they found that an injection of this tracer could reveal heart damage up to 30 hours after an interruption in blood flow (cardiac ischemia).

Normally the heart burns fatty acids as its main fuel. Ischemia causes the heart to use glucose (blood sugar) instead. The tracer works by detecting this use of glucose.

The researchers touted the new tracer as way physicians could one day routinely use to detect cardiac ischemia without a stress test, even hours after chest pain has ended.

The study has been published in the online issue of the journal Circulation.

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