Significance of the time course of ST segment elevation just after reperfusion therapy for acute myocardial infarction
Mori, F.; Uchida, T.; Byun, T.; Kasanuki, H.
Journal of Cardiology 35(1): 1-8
2000
ISSN/ISBN: 0914-5087 PMID: 10654244 Document Number: 518515
The significance of the time course of ST segment elevation just after reperfusion therapy for acute myocardial infarction was investigated in 25 consecutive patients with acute myocardial infarction and ST elevation. The most elevated ST lead from the standard electrocardiogram on admission was continuously monitored as the ST trend for 72 hr including during the reperfusion procedure. The culprit artery was totally occluded and reperfused without flow delay. Left ventriculograms were obtained after reperfusion and 3-4 weeks later. The most elevated ST level before reperfusion was measured as the maximal level and the ST level 30 min after reperfusion as the reperfused level. The patients were divided into 2 groups, group ST > or = 50% (n = 12) with a decrease of less than 50% of the maximal ST level and group ST < 50% (n = 13) with a decrease of 50% or over 50%. Regional left ventricular wall motion of infarct site, end-diastolic left ventricular volume and ejection fraction were compared between the acute and chronic phase left ventriculograms in each group. In group ST > or = 50%, no significant change was detected in both regional and global ejection fraction, whereas end-diastolic left ventricular volume enlarged significantly in the chronic phase (acute 80 +/- 25 ml/m2 to chronic 95 +/- 17 ml/m2, p < 0.01). In group ST < 50%, regional and global ejection fraction both improved significantly (SD/chord: acute -2.2 +/- 1.5 to chronic -1.4 +/- 0.4, p < 0.001; ejection fraction: acute 50 +/- 14% to chronic 57 +/- 13%, p < 0.01) but end-diastolic left ventricular volume remained the same in the chronic phase. The peak creatine kinase level and the frequency of ST re-elevation at reperfusion were significantly higher in group ST > or = 50% than in group ST < 50% (creatine kinase: group ST > or = 50% 5,496 +/- 2,219 IU/l, group ST < 50% 1,913 +/- 1,180 IU/l, p < 0.0001; ST re-elevation: group ST > or = 50% 83%, group ST < 50% 38%, p < 0.05), although the time from onset of myocardial infarction to reperfusion, the maximal ST level, the degree of collateral development, and the frequency of pre-infarction angina were not different between the 2 groups. Rapid resolution of ST elevation after reperfusion is a useful marker of the improvement of left ventricular function in acute myocardial infarction.