No wonder emergency room physicians and hospital administrators are eyeing several cardiovascular imaging technologies. Myocardial contrast echocardiography (MCE) is among them, and a new study suggests it may be an attractive option in many patients presenting with chest pain. Dr. Diana Rinkevich and colleagues from the University of Virginia, Charlottesville, found that a perfusion abnormality on MCE reliably identified patients with myocardial infarction (MI), as well as those who were likely to experience other serious cardiac problems in the future.

The study involved 200 patients. After baseline assessment of left ventricular function, MCE was performed using a continuous infusion of human albumin microspheres during high-power intermittent harmonic imaging.

All three myocardial perfusion beds could be interpreted in 153 patients (77%), and perfusion defects were observed in 61. Of these, 21 experienced cardiac problems during hospitalization, including 14 who were confirmed to have an MI, two who developed unstable angina, and five who developed heart failure. Only one patient without a perfusion defect developed a cardiac complication, unstable angina. The difference between the two groups was statistically significant.

On multivariate analysis, only an elevated troponin level was found to predict cardiac events during hospitalization more strongly than perfusion abnormality on MCE, increasing the risk nine-fold, as compared with 7.4-fold. Cardiac enzyme levels may not yield a diagnosis for some 12 hours or more, however, and the researchers concluded that perfusion abnormalities on MCE may be a more useful tool for early evaluation.

During a follow-up that averaged seven months, patients experienced an additional eight cardiac complications, a finding that was more common among patients with a perfusion defect on the initial emergency room echocardiogram. The prognostic link did not achieve statistical significance, however.