Is There Any Impact of ST Re-elevation on Patients With Acute Myocardial Infarction Following Reperfusion Therapy?

Abstract

re-elevation, despite initial ST resolution, occurred in 23% of the patients, and was associated with poorer EF at 6 months. They divided their patients into 3 groups (ST resolution without re-elevation, ST resolution with reelevation, and no ST resolution), and showed the serial ECG changes (Figure). In this issue of the Journal, Cuenin et al 8 report that 19% of 662 patients experienced ST segment re-elevation, but there were no differences in EF or death at 1 year between patients with and without re-elevation. Although the incidence of ST re-elevation was similar to that reported by Okuda et al, the effect on EF was inconsistent. Several differences between the 2 studies may have influenced the results. First, the timing of evaluation for ST re-elevation was different. Most previous studies evaluated ST resolution within several hours after reperfusion therapy, and ST resolution was consistently associated with better clinical outcomes. The mechanism of ST re-elevation is unclear and its occurrence suggests the possibility of re-infarction or pericarditis. In fact, stent P rimary percutaneous coronary intervention (PCI) to recanalize an occluded artery has been the main treatment for acute myocardial infarction (AMI), but a substantial number of patients still develop large infarcts. Impaired microvascular reperfusion, which is evaluated by the absence of resolution of ST-segment elevation (ST resolution) on the 12-lead ECG following reperfusion therapy, is considered to be associated with worse final TIMI (Thrombolysis in Myocardial Infarction) flow grade and large infarcts. 1 Furthermore, the measure of ST resolution has been reported to correlate with left ventricular function, survival, and reinfarction during longterm follow-up after both primary PCI and thrombolytic therapy. 1-7 ST resolution occurs in 64-85% of patients, as shown in the Table. Only a few previous reports have investigated the prevalence of ST segment re-elevation even though ECG is a standard and simple diagnostic modality. Matano et al reported that ST re-elevation occurred in 29% of the patients, but that there was no difference in ejection fraction (EF) at 1 month between the patients with and without ST re-elevation. 4 In contrast, Okuda et al 6 reported that ST