[Non-invasive evaluation of coronary reperfusion. Analysis of the ST segment before and after thrombolysis in acute myocardial infarct].

BACKGROUND

The aim of this study was to determine the role of the ST segment elevation resolution > 50% between the ECG before and 2 hours after thrombolytic therapy as a predictor of acute myocardial infarction (AMI)-related artery patency, assessed by a coronary angiography performed 1 month after AMI.

MATERIALS AND METHODS

This study enrolled 95 patients, 75 men and 20 women, 58 years mean aged, admitted to the coronary care unit with diagnosis of AMI. Patients were treated with thrombolysis within 6 hours from the onset of chest pain, according to the GUSTO trial.

RESULTS

The findings showed a significant prevalence of ST segment elevation resolution > 50% in inferior AMI (p < 0.01). It has been observed that the ST segment resolution is correlated with lower (p < 0.01) and earlier (p < 0.05) peak in serum creatinekinase (CK) and CK MB release and with less damage of left ventricular ejection fraction assessed by ventriculography (p < 0.01). All these findings indicated a lower extensive myocardial damage. Patients with ST segment resolution presented a prevalence of one or two-coronary vessel disease, with an infarct-related vessel narrowing like that observed in the other patients without ST resolution. Nevertheless a TIMI grade 2 or 3 flow was observed more frequently, but not significantly, in the subjects with ST resolution; a significant prevalence was limited to TIMI 3 grade flow (p < 0.05). In the present study ST segment elevation resolution > 50% represented a highly sensitive and a poor specific predictor of vessel patency in inferior AMI, but with a poor sensitivity and specificity in anterior AMI.

CONCLUSIONS

Personal experience suggested that the thrombolytic therapy has a less favourable effect on the artery patency assessed 1 month after AMI, rather than in the acute phase as reported in previous studies. Dynamic changes of flow or a following worsening in atherosclerotic plaque could be probably responsible of reocclusion of an initially reperfused coronary artery.