Time to Treatment Influences the Impact of ST-Segment Resolution on One-Year Prognosis

Abstract

Background-Early ST resolution after reperfusion is a prognostic indicator in acute myocardial infarction. Little information exists regarding the prognostic utility of ST resolution beyond 4 hours after fibrinolysis. Furthermore, the relation between time to treatment, ST resolution at 24 to 36 hours, and 1-year outcome has not been well studied. Accordingly, we undertook a prospective ECG substudy in the Assessment of the Safety and Efficacy of a New Thrombolytic (ASSENT-2) trial to examine this. Methods and Results-Patients (nϭ13 100) were stratified into 3 ST-resolution categories, based on baseline and 24-to 36-hour ECGs: complete resolution (Ն70%) in 6698 (51.1%) patients, partial resolution (30% to 70%) in 4610 (35.2%) patients, and no resolution (Ͻ30%) in 1792 (13.7%) patients; 1-year mortality rate was 5.1%, 8.0%, and 9.7%, respectively (PϽ0.001). Among patients treated Ͻ2 hours after symptom onset, 55.6% had complete ST resolution, whereas 52.1% and 43% of patients treated between 2 to 4 hours and 4 to 6 hours, respectively, had complete ST resolution (PϽ0.001). Within each category of ST resolution, patients treated Ͻ2 hours had lower 1-year mortality rates as compared with patients treated between 2 to 4 hours or Ͼ4 hours (3.8% versus 5.2% and 6.6%, Pϭ0.002 in complete ST resolution; 5.7% versus 8.4% and 9.9%, Pϭ0.001 in partial ST resolution; 7.1% versus 8.7% and 13%, Pϭ0.006 in no resolution). The extent of ST resolution was closely and inversely correlated with 1-year mortality rates (rϭϪ0.963, PϽ0.001). Conclusions-ST resolution at 24 to 36 hours after fibrinolysis is influenced by time to treatment and inversely related to 1-year mortality rates. Time to treatment further differentiates between high-and low-risk patients and further highlights the importance of reducing time delay to initiation of fibrinolysis in acute myocardial infarction. (Circulation. 2001;

Association between admission mean platelet volume and ST segment resolution after thrombolytic therapy for acute myocardial infarction

“…Several studies demonstrated that greater ST-segment resolution was associated with higher rates of IRA patency, less residual stenosis at angiography, smaller infarct size and better left ventricular systolic function (14,15,18). It was also shown that, ST-segment resolution was associated with lower 30 days and 1 year mortality rates (17,19). When complete ST segment resolution is seen, successful reperfusion appears to have occurred at the tissue level (17).…”

Clinical characteristics and outcomes of acute coronary syndrome patients with left anterior hemiblock

“…The admission ECGs were read at the Canadian Heart Research Centre electrocardiographic core laboratories by trained physicians blinded to site interpretation, patient characteristics and outcomes. Previous studies have validated the ECG analysis by the core laboratory, with intraobserver and interobserver agreement of 100% and 93–99%, respectively 18 19. Patients with left bundle branch block, poor quality/incomplete ECG, and ventricular paced rhythms were excluded (n=707).…”

A comparative study on the effect of streptokinase between diabetic and non-diabetic myocardial infarction patients

“…Complete ST-resolution (≥70% ST-resolution) in patients with acute myocardial infarction, most likely identifies patients with successful reperfusion following streptokinase therapy and these patients proved to be a very low-risk group with good prognosis whereas failed or no ST-resolution (<30% ST-resolution) identifies patients with failed myocardial reperfusion, which means that these patients have a higher risk for an adverse outcome. However, partial ST-resolution (<70 to 30%) is related to impairment of reperfusion at the myocardial level reflecting the unpredictable effect of streptokinase (Yuling et al, 2001;Zeymer et al, 2001). …”