Clinical implications of persistent ST segment depression after admission in patients with non-ST segment elevation acute coronary syndrome

Abstract

We studied 190 consecutive patients with NSTE-ACS who had chest pain suggesting cardiac ischaemia within 24 hours before admission, involving an unstable pattern of pain, consisting of rest pain, new onset, severe or frequent angina, accelerating angina, or angina occurring within 21 days after an acute myocardial infarction. A 12 lead ECG was recorded on admission, six hours after admission, and at discharge, at a paper speed of 25 mm/s and an amplification of 10 mm/mV. ST segment depression ⩾ 1.0 mm was considered significant.² ST resolution was defined as a reduction of ⩾ 50% in the sum of ST segment depression in all leads, except for lead aVR, between ECGs on admission and six hours after admission. On admission, C reactive protein concentrations were measured by N Latex CRP Mono tests, performed on a Behring BN II Nephelometer (Behring Diagnostics) using polystyrene microbeads coated with monoclonal mouse antibodies; a rapid qualitative assay for cardiac specific troponin T (Trop T, Roche Diagnostics, detection limit, 0.1 ng/ml) was also performed. In patients who were negative for troponin within six hours after the onset of symptoms, the test was repeated at 8–12 hours.³ In all patients, cardiac catheterisation was performed a median of four days after admission, excluding urgent cardiac catheterisation. In patients with a single defined culprit lesion, the details of the lesion (morphologic characteristics⁴ and presence of thrombus) and the thrombolysis in myocardial infarction (TIMI) flow grade and myocardial blush grade⁵ were examined. All ECG and angiographic findings were evaluated by two blinded observers.