Background: Early resolution of ST-segment elevation (ST-segment recovery) is associated with an improved outcome after infarction. Whether this relation is present in patients with Thrombolysis In Myocardial Infarction (TIMI) grade 2 or 3 flow (ie, patent) infarct-related arteries is not known.
Methods and results: To examine the associations between time to achieve stable 50% ST-segment recovery assessed by continuous ECG monitoring, infarct artery flow, and infarct zone wall motion (at 48 hours), we studied 134 patients who underwent angiography at 99 (interquartile range 92 to 110) minutes after commencing streptokinase, initiated within 12 hours of onset of symptoms of myocardial infarction. Patients with TIMI 2 or 3 flow who failed to achieve early stable ST-segment recovery (50% ST-segment recovery sustained for > or 4 hours with <100 microV change in the peak lead) by 60 or 90 minutes had a higher fraction of chords in the infarct zone >2 SD below normal wall motion (TIMI 2: 55.5% vs 15.3%, P=0.006; and 56.5% vs 26.8%, P=0.01, respectively; and TIMI 3: 48.8% vs 28.3%, P=0.07; and 51.8% vs 29.9%, P=0.03, respectively). Time to stable ST-segment recovery was a multivariate predictor of infarct zone wall motion (P=0.04) independent of TIMI flow grade and the time from symptom onset to streptokinase therapy.
Conclusions: In patients with TIMI 2 or 3 flow in infarct-related artery, early stable ST-segment recovery is associated with improved infarct zone wall motion at 48 hours. ST-segment recovery may provide additional information about the degree of myocyte reperfusion achieved in patients with a patent epicardial infarct-related artery after thrombolytic therapy.