Noninvasive identification of myocardium at risk in patients with acute myocardial infarction and nondiagnostic electrocardiograms with technetium-99m-Sestamibi.
BACKGROUND
Patients who have chest pain without electrocardiographic ST elevation are not candidates for thrombolytic therapy in most clinical trials. This study examined the value of technetium-99m-Sestamibi tomographic imaging to assess myocardial perfusion in patients during chest pain without ST elevation.


RESULTS
Tc-99m-Sestamibi was injected in 14 patients who had chest pain without ST elevation, who subsequently developed enzymatic evidence of myocardial infarction within 24 hours. Tomographic imaging was performed 1-6 hours after injection. Thirteen of 14 patients showed significant perfusion defects indicative of acute myocardial infarction consistent with absent perfusion (20 +/- 15% of the left ventricle; range, 2-53%); one patient had normal images. Because of the absence of definitive electrocardiographic changes, only five patients received reperfusion therapy within 6 hours of the onset of chest pain. Regional wall motion abnormalities were present in nine of nine patients undergoing contrast ventriculography and correlated with the location of the Tc-99m-Sestamibi perfusion defect. At the time of subsequent coronary angiography, total arterial occlusion was present in 11 of the 14 patients. The infarct-related artery could be identified in 13 of the 14 patients. In six of these 13 patients, the left circumflex was the infarct-related artery.


CONCLUSIONS
Patients who have chest pain without electrocardiographic ST elevation may have arterial occlusion and significant myocardium at risk. Tc-99m-Sestamibi imaging may be of benefit in identifying these patients early so that they can be considered for acute reperfusion therapy.
Christian
T F
TF
Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic and Foundation, Rochester, Minn. 55905.
Clements
I P
IP
Gibbons
R J
RJ
D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D017023:Coronary Angiography; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology*; D015609:Organotechnetium Compounds; D012307:Risk Factors; D017256:Technetium Tc 99m Sestamibi; D014054:Tomography
D015609:Organotechnetium Compounds; D017256:Technetium Tc 99m Sestamibi