Cardiac troponin T (cTnT), a new marker of myocardial tissue damage, was investigated in 32 consecutive multiply injured patients. cTnT, creatine kinase (CK) and CK isoenzyme MB (CK-MB) mass concentrations were measured immediately after admission, 12 and 24 h later and daily thereafter for 4 days. We found a moderate increase in cTnT in 22 patients (72 per cent; peaks: 0.6-5.1 micrograms/l). In only four of these 22 patients did the CK-MB mass/CK index indicate myocardial injury. ST-T alterations and arrhythmias did not occur significantly more frequently in patients with increased cTnT plasma concentrations or positive CK-MB mass/CK index. We found a moderate increase in cTnT in 72 per cent of all patients with multiple injuries, but we found no association between an increase in cTnT and the occurrence of electrocardiographic changes and arrhythmias.