Background: Myocardial contusion during blunt chest trauma is common and may lead to potentially fatal cardiac complications. Therefore, it is useful to identify a serum marker reflecting the myocardial damage that can predict risk for cardiac complications. In this study, the authors determined the strength of the association between cardiac troponin I (cTnI) levels and the risk of arrhythmia or the development of left ventricular dysfunction in a cohort of patients with blunt chest trauma.
Methods and results: In 187 multiply injured patients with blunt chest trauma, serial measurements of cTnI, total creatine kinase (CK), and isoenzyme of creatine kinase with muscle and brain subunits (CK-MB) were combined with sequential electrocardigraphic and echocardiographic recordings. The results showed that 63 patients (34%) had myocardial contusion, as defined by positive cTnI levels, of which 47 (25%) were symptomatic and 16 (9%) showed no abnormalities. The remaining 124 patients (66%) displaying negative CTnI levels were asymptomatic during the entire study. Severity of arrhythmia correlated directly with increase in cTnI levels. The levels of cTnI in the symptomatic group remained elevated significantly longer than the levels in the asymptomatic group. The depression of left ventricular ejection fraction was inversely correlated with the increase in cTn levels. The patients whose cTnI levels were below 1.05 microg/L at admission and during the first 6 hours afterward showed no cardiac abnormalities throughout the entire study period
Conclusions: Levels of cTnI below 1.05 microg/L in asymptomatic patients at admission and within the first 6 hours after admission rule out myocardial injury, whereas positive cTn levels above 1.05 microg/L mandate further cardiologic workup for the detection and management of myocardial injury. Furthermore, the dynamics and peak levels of pathologic cTnI levels allow estimation of arrhythmia risk and left ventricular dysfunction in trauma patients with myocardial contusion.