Emergency room technetium-99m sestamibi imaging to rule out acute myocardial ischemic events in patients with nondiagnostic electrocardiograms.

OBJECTIVES: The goal of this study was to determine the role of nuclear imaging in patients with chest pain.
BACKGROUND: The diagnosis of myocardial ischemic events in patients with chest pain and a nondiagnostic electrocardiogram (ECG) is problematic.
METHODS: Rest tomographic technetium-99m sestamibi imaging (740 MBq intravenously) was performed in 64 patients presenting to the emergency room with chest pain of suspected cardiac origin and a nondiagnostic ECG. Patients were admitted to the coronary care unit on the basis of clinical criteria only and were strictly monitored.
RESULTS: Thirty patients showed a perfusion defect on admission. Of these, 13 developed myocardial infarction within 12 h. Coronary artery disease was diagnosed in 14 patients and the remaining 3 patients were classified as having false positive findings. Normal perfusion scans were seen in 34 patients, none of whom were ultimately diagnosed as having coronary artery disease. A 100% sensitivity was demonstrated versus the final diagnosis of acute cardiac ischemia (kappa 0.91, 95% confidence interval 0.8 to 1.0). A follow-up period of up to 18 months (mean 11 +/- 3) was also carried out for major cardiac events (death, myocardial infarction, coronary angioplasty and coronary artery bypass grafting). Six events (two coronary bypass procedures, three angioplasty procedures and one death) were observed at follow-up in the group of patients with a technetium-99m sestamibi perfusion defect. Patients with normal perfusion scans on admission had no major cardiac events at follow-up study.
CONCLUSIONS: Technetium-99m sestamibi perfusion imaging is a promising technique for ruling out acute myocardial ischemia in the emergency room. More efficient utilization of intensive therapy beds may be expected with this approach.