Use of resting myocardial scintigraphy during chest pain to exclude diagnosis of acute myocardial infarction.
BACKGROUND
Images of myocardial perfusion taken during an episode of chest pain have been used for patients in the emergency department.


OBJECTIVE
To evaluate the operating characteristics of 99mTc-Tetrofosmin scintigraphy during an episode of chest pain to exclude the diagnosis of acute myocardial infarction.


METHODS
One hundred and eight patients admitted with chest pain, or up to four hours after the end of symptoms and nondiagnostic electrocardiogram, underwent resting scintigraphy and measurement of troponin I concentrations. Patients with a history of myocardial infarction (MI) were not excluded (24 patients). Troponin I concentrations were determined at admission and 6 hours later. Nuclear physicians performed a blind analysis of the images, and myocardial infarction was confirmed whenever troponin I level increase was three times that of the control.


RESULTS
Resting perfusion image was abnormal in all 6 patients with MI. Only 1 patient had a normal image and increased troponin levels. Fifty-five patients had positive images without MI, and 46 patients had normal images and troponin levels. The prevalence of the disease was 6.5%. The sensitivity and specificity of the resting images during an episode of chest pain to diagnose MI was 85.7% and 45.5%, respectively. The negative predictive value was 97.7%.


CONCLUSIONS
Patients undergoing chest pain protocol with SPECT showed an excellent negative predictive value to exclude diagnosis of myocardial infarction. These results suggest that resting perfusion image is an important tool at the chest pain unit.
Barbirato
Gustavo Borges
GB
Centro de Estudos do Hospital Pró-Cardíaco, Rua Baronesa de Poconé 71/1004, Lagoa, Rio de Janeiro, RJ, Brazil. gbarbirato@cardiol.br
Azevedo
Jader Cunha de
JC
Felix
Renata Christian Martins
RC
Correa
Patricia Lavatori
PL
Volschan
André
A
Viegas
Monica
M
Pimenta
Lucia
L
Dohmann
Hans Fernando Rocha
HF
Mesquita
Evandro Tinoco
ET
Mesquita
Claudio Tinoco
CT
D015415:Biomarkers / Q000097:blood; D001938:Brazil; D002637:Chest Pain / Q000097:blood / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000000981:diagnostic imaging*; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012146:Rest; D019210:Troponin I / Q000097:blood
D015415:Biomarkers; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D019210:Troponin I; C078700:technetium tc-99m tetrofosmin