Dobutamine-induced ST-segment elevation in patients with healed myocardial infarction. A marker of myocardial viability.

The purpose of this study was to determine the significance of transient ST-segment elevation during dobutamine infusions in patients with healed Q wave myocardial infarction. Twenty-seven patients with previous Q wave myocardial infarction were studied prospectively with dobutamine-thallium-201 single-photon emission computed tomography. The presence of ST-segment elevation in leads with Q waves was related to thallium reversibility at 4-hour redistribution imaging or after reinjection, to residual flow, as well as to wall motion abnormalities in the infarcted zone. ST-segment elevation in infarct-related leads was observed in 15 patients; 11 (73%) showed viability by thallium-201 in the infarcted zone. In patients without ST-segment elevation, viability was shown less frequently (33%, P < .05). Hypokinesis in infarcted segments was present in 60% of patients with ST-segment elevation and in 25% of patients without ST-segment elevation (.05 < P < .1). Finally, infarct-related artery was patent and/or collaterals were present in 10 patients with ST-segment elevation (67%) and in 4 patients without (33%, .05 < P < .1). In conclusion, ST-segment elevation during dobutamine infusion is a marker of residual viability in infarcted segments.