Clinical implications of a next-day follow-up electrocardiogram in patients with non-ST elevation acute coronary syndromes.Am Heart J. 2008 Oct; 156(4):797-803.AH
The prognostic value of admission ST-segment changes in patients with non-ST elevation acute coronary syndromes (NSTE ACS) is well established; however, the value of a next-day follow-up electrocardiogram (ECG) is unclear.
We evaluated ST-depression (ST(downward arrow)) and Q-wave status on the admission and 24 to 36-hour follow-up ECG in 2,743 patients in a prospective Canadian ACS registry.
Of patients with ST(downward arrow) > or =1 mm on admission (n = 533 [19.4%]), 366 (68.7%) normalized their ST segment on follow-up ECG. Among patients without ST(downward arrow) on admission (n = 2,110), 97 (4.4%) developed new ST(downward arrow) at follow-up. Patients with normalized ST(downward arrow) at follow-up had higher 1-year myocardial infarction (MI) (10.1% vs 5.7%, odds ratio [OR] 1.77, 95% CI 1.12-2.81, P = .015) and death/MI rates (19.5% vs 10.2%, OR 1.69, 95% CI 1.18-2.41, P = .004), respectively, as compared to those who never had ST(downward arrow). Patients with persistent ST(downward arrow) had higher 1-year MI (10.8% vs 5.7%, OR 1.95, 95% CI 1.09-3.51, P = .025) and death/MI rates (25.6% vs 10.2%, OR 1.78, 95% CI 1.13-2.79, P = .013), respectively. In multivariable analysis, ST(downward arrow) on baseline ECG was an independent predictor of 1-year mortality; however, ST(downward arrow) on the follow-up ECG did not provide additional prognostic value. There were no differences in outcomes between the 4 different Q-wave status groups.
Although dynamic and persistent ST(downward arrow) are associated with worse unadjusted outcome in patients with NSTE ACS, there was no incremental prognostic value of a follow-up ECG evaluating ST depression and/or Q-wave status beyond that already provided by the initial ECG together with established prognostic factors.