AN EVALUATION OF SERUM TROPONIN-T AND SIGNAL-AVERAGED ELECTROCARDIOGRAPHY IN PREDICTING ELECTROCARDIOGRAPHIC ABNORMALITIES AFTER BLUNT CHEST TRAUMA

Objective: Despite multiple inquiries, there are no available tests to definitively detect blunt myocardial injury, The evaluation of patien ts with chest wall injuries without other indications for intensive ca re unit (ICU) admission has ranged from a single emergency department electrocardiogram (ECG) to 72 hours of continuous electrocardiographic monitoring. Recently, signal-averaged ECG and serum cardiac troponin T have demonstrated clinical utility in the evaluation of ischemic hea rt disease, The purpose of this study is to determine the ability of t hese diagnostic tests to predict the occurrence of significant electro cardiographic rhythm disturbances for patients with chest wall injurie s and no other indication for ICU admission, Methods: We prospectively evaluated 71 consecutive adult patients admitted to a regional Level I trauma tenter with chest wall injuries not requiring ICU admission, We obtained admission signal-averaged EGG, serum troponin T level, sta ndard EGG, and creatine phosphokinase (CPK-MB) level, Patients receive d continuous electrocardiographic monitoring, follow-up 12-lead etectr ocardiography, and serial monitoring of troponin and CPK-MB, Echocardi ography was performed for patients with abnormal CPK-MB levels, Electr ocardiographic events were graded as normal, abnormal but clinically i nsignificant, or clinically significant, Multiple stepwise logistic re gression analysis was used to evaluate predictors for the development of clinically significant electrocardiographic events. Results: On adm ission, 17 of 71 patients (23.9%) had normal sinus rhythm; 13 (18.3%) had a clinically significant finding, For 50 patients, follow-up ECG w as abnormal; for 26, the findings were clinically significant. Of 17 p atients with normal initial ECGs, 7 (41%) developed a clinically signi ficant abnormality, Six patients received intervention for ECG finding s, Eleven of 71 patients (16%) had positive troponin T; 5 of 71 (7%) h ad positive CPK-MB; 15 of 71 (21%) had positive signal-averaged EGG; a nd ii of 13 had positive echocardiograms. Initial electrocardiographic abnormalities and a troponin T level > 0.20 mu g/L were the only vari ables found to predict clinically significant electrocardiographic eve nts. Sensitivity and specificity of troponin T in predicting clinicall y significant abnormalities were 27 and 91%, respectively. Conclusions : 1, The hest predictors for the development of significant electrocar diographic changes are an admission ECG abnormality and an elevated se rum troponin T level, 2, Both tests have high specificity with low to moderate sensitivity, 3, Patients with normal ECGs may develop clinica lly significant events, 4, CPK-MB and echocardiograms continue to be p oor predictors of significant electrocardiographic events.