[Evaluation of healing process in myocardial infarction by the time course of serum myosin light chain I: the effects of early reperfusion].

The effects of early reperfusion on the infarct area were evaluated by measuring the plasma creatine phosphokinase (CPK) activity and myosin light chain I (LCI) in 30 patients with acute myocardial infarction. Twenty of these patients underwent coronary angiography, of whom 9 had reperfusion with successful intracoronary thrombolysis, which revealed significant correlations between peak values of LCI and peak values of CPK or CPK-MB activity (r = 0.775, p < 0.01 or r = 0.783, p < 0.01). Similarly, peak value of LCI correlated with left ventricular ejection fraction (r = -0.729, p < 0.01) and the infarct size which was estimated according to the extent and severity scores measured by Tl-201 myocardial SPECT (vs extent score, r = 0.439, p < 0.05; vs severity score, r = 0.429, p < 0.05). The time activity curves of plasma CPK activity and LCI differed in patients with and without reperfusion; in the former, mean peak values of CPK activity and LCI were 1,170 +/- 321 U/L (mean +/- SD) and 10.7 +/- 3.5 ng/ml, respectively, while in the latter, they were 5,430 +/- 3,315 U/L and 25.2 +/- 12.9 ng/ml, respectively. The times to peak values of LCI and CPK did not differ between these 2 patient groups. We concluded that the early reperfusion suppresses the progressive extension of irreversible injury in the infarct area and significantly diminishes the infarct size.