Prognostic Significance Of Evolving St-Segment Depression On Admission And Early Repeat Electrocardiograms In Non-St Elevation Acute Coronary Syndromes - Insights From The Superior Yield Of The New Strategy Of Enoxaparin, Revascularization And Glycoprotein Ilb/Illa Inhibitor (Synergy) Trial

The presence of ST-segment depression (STD) on admission is well recognized to confer adverse prognosis in patients with non-ST-elevation acute coronary syndromes (NST-ACS). However, the incremental prognostic value of STD on electrocardiogram (ECG) obtained early after admission has not been well examined. Furthermore, whether quantitative evaluation of initial and early dynamic STD evolution may improve risk stratification remains undetermined. In this SYNERGY ECG substudy, serial ECGs recorded routinely on initial admission and at 12 hours after admission among 3918 participants with NST-ACS were analyzed at core laboratory for the presence of STD (≥1mm in any lead except aVR) and STD quantification (maximum magnitude in any lead with STD≥1mm except aVR). Patient outcomes were compared according to the presence of STD on each of the two serial ECGs. Cox regression model was used to examine the independent predictive value of quantitative STD on admission and at 12 hours for death and/or recurrent myocardial infarction (death/re-MI) at 6 months. The incidence of 6-month death/re-MI is summarized below: After adjusting for treatment assignment and patient characteristics of prognostic significance in the SYNERGY trial (age, gender, ethnicity, diabetes, prior MI, smoking, heart rate, serum creatinine and cardiac enzymes), quantitative STD both on admission (Hazard Ratio (HR) per 1mm STD=1.14 95%CI=1.04–1.26, P=0.003) and at 12 hours after admission (HR per 1mm STD=1.17, 95%CI=1.01–1.35, P=0.03) were each independently predictive of 6-month death/re-MI. The presence and extent of STD on ECG obtained 12 hours after admission provide independent prognostic information beyond that afforded by the initial admission ECG. Incorporating a routine 12 hour ECG and its quantitative evaluation for early dynamic STD evolution may further refine risk stratification of patients with NST-ACS.