[Estimation of myocardial damage after cardiac surgery by myosin light chain I and troponin T].

The purpose of the study was to test cardiac myosin light chain I (MLCI) and troponin T (TNT) as markers of myocardial damage after heart surgery. Forty-three patients undergoing cardiac surgery were arbitrarily divided into three groups according to the creatine kinase MB isoenzyme (CK-MB) levels and postoperative electrocardiogram (ECG) changes. Group 1: CK MB > 100 micrograms/l and Infarction pattern changes in ECG (Infarction): Group 2: CK-MB < 100 micrograms/l and no ECG changes (minimal myocardial damage). Group 3: CK-MB > 100 micrograms/l or non specific ECG changes (myocardial injury). MLCI levels showed strong correlations with TNT levels after the operation. The peak MLCI and TNT levels in group 1 were significantly higher than in group 2. The peak MLCI in group 1 was significantly higher than in group 3. TNT showed different patterns in the Infarction and Injury groups. The study showed that MLCI and TNT estimation could evaluate myocardial damage over several postoperative days. TNT estimation could identify myocardial damage earlier than MLCI, however MLCI could discriminate perioperative infarction better than TNT.