Comparison of 2-dimensional echocardiography and myocardial perfusion imaging for diagnosing myocardial infarction in emergency department patients.
BACKGROUND
Both 2-dimensional echocardiography and myocardial perfusion imaging (MPI) with technetium-99m based agents have been used to identify patients in the emergency department with myocardial infarction (MI). However, the inclusion of small numbers of patients in prior studies limits the accurate assessment of sensitivity of the 2 techniques.


METHODS
Gated MPI was used as part of the initial triage process in patients initially considered at low to moderate risk for acute coronary syndromes (no ST elevation or depression). Patients diagnosed with MI also underwent echocardiography. MPI results were considered positive if there was a perfusion defect associated with abnormal wall motion or thickening, and echocardiographic results were considered positive if there were segmental wall motion abnormalities or ejection fraction of less than 40%.


RESULTS
Both tests were performed on 141 patients. The sensitivities for MI for echocardiography (91%; 95% CI, 86%-95%) and MPI (89%; 95% CI, 83%-94%) were similar. Patients who had either negative echocardiographic results (peak creatine kinase level [CK], 325 +/- 206 vs 582 +/- 614 U/L; P =.003) or negative MPI results (peak CK, 313 +/- 227 vs 590 +/- 620 U/L; P =.001) had smaller MIs as estimated with peak CK values. Ejection fraction was highly correlated between the 2 techniques (r = 0.82; P <.001).


CONCLUSIONS
Both echocardiography and MPI have a high sensitivity for identifying patients in the emergency department who have MI. False negative studies with either technique were associated with small MIs.
Kontos
Michael C
MC
Department of Internal Medicine (Cardiology), Medical College of Virginia, Campus of Virginia Commonwealth University, Richmond, Va, USA.
Kurdziel
Karen
K
McQueen
Robert
R
Arrowood
James A
JA
Jesse
Robert L
RL
Ornato
Joseph P
JP
Paulsen
Walter H P
WH
Tatum
James L
JL
Nixon
J V
JV
D015415:Biomarkers / Q000097:blood; D016507:Cardiology Service, Hospital; D004796:Clinical Enzyme Tests; D003402:Creatine Kinase / Q000097:blood; D004452:Echocardiography; D004636:Emergency Service, Hospital; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi
D015415:Biomarkers; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin; D017256:Technetium Tc 99m Sestamibi; D003402:Creatine Kinase