Usefulness of quantitative versus qualitative ST-segment depression for risk stratification of non-ST elevation acute coronary syndromes in contemporary clinical practice.

This aim of this study was to assess the clinical utility of quantitative ST-segment depression (STD) for refining the risk stratification of non-ST elevation acute coronary syndromes in the prospective, multinational Global Registry of Acute Coronary Events (GRACE). Quantitative measurements of STD on admission electrocardiograms were evaluated independently by a core laboratory, and their predictive value for in-hospital and cumulative 6-month mortality was examined. Although more severe STD is a marker of increased short- and long-term mortality, it is also associated with higher risk clinical features and biomarkers. Thus, after adjustment for these clinically important predictors, quantitative STD does not provide incremental prognostic value beyond simple dichotomous evaluation for the presence of STD. Furthermore, adopting quantitative instead of the prognostically proven qualitative evaluation of STD does not improve risk discrimination afforded by the validated GRACE risk models. In conclusion, the findings do not support the quantification of STD in routine clinical practice beyond simple evaluation for the presence of STD as an integral part of comprehensive risk stratification using the GRACE risk score.

Local hospital vs. core-laboratory interpretation of the admission electrocardiogram in acute coronary syndromes: increased mortality in patients with unrecognized ST-elevation myocardial infarction.

AIMS: Previous analyses suggest only modest agreement between local site and core-laboratory (core-lab) electrocardiogram (ECG) interpretation in patients with acute coronary syndromes (ACSs); however, this has not been well examined outside of clinical trial populations. METHODS AND RESULTS: Patients (n = 5277 from 51 hospitals; 4916 with 1 year vital status) participating in the Canadian ACS Registry who were hospitalized with an ACS and had an interpretable initial ECG were included in this study. Core-lab ECG interpretation was blinded to site interpretation and outcomes. There was moderate agreement between site and core-lab regarding the predominant ECG findings (kappa = 0.49). Patients with core-lab-defined ST-elevation and cardiac marker elevation (n = 1202) not classified as ST-elevation by the site were less likely to receive acetylsalicylic acid (ASA) (90 vs. 96%, P < 0.0001), heparin (91 vs. 95%, P = 0.04), and reperfusion therapy (14 vs. 76%, P < 0.0001) than patients for whom there was agreement that ST-elevation was present. After adjusting for other validated prognostic factors, site-unrecognized ST-elevation was independently associated with higher mortality (odds ratio = 2.21; 95% CI, 1.46-3.36; P < 0.001). CONCLUSIONS: In patients with ACS, there was only moderate agreement between core-lab and site interpretation of the initial ECG. Site-unrecognized ST-elevation myocardial infarction was associated with underutilization of evidence-based therapies and increased 1-year mortality.

Differences between local hospital and core laboratory interpretation of the admission electrocardiogram in patients with acute coronary syndromes and their relation to outcome.

In the prospective, multinational Global Registry of Acute Coronary Events (GRACE), patients diagnosed with non-ST-elevation acute coronary syndromes had their admission electrocardiogram independently evaluated by a central core laboratory, and its interpretation by the core laboratory and enrolling site were compared. One in 6 of these patients had clinically important features of left-bundle branch block or ST-segment deviation diagnosed by the core laboratory that were apparently not recognized at the local sites; this subgroup of patients was less likely to undergo risk stratification and revascularization. Importantly, failure to recognize these features as confirmed by the core laboratory in routine clinical practice was independently associated with higher mortality and recurrent myocardial infarction at 6 months (adjusted odds ratio 1.41, 95% confidence interval 1.01 to 1.96, p = 0.043). In conclusion, these findings underscore an urgent need to promote more accurate interpretation of electrocardiograms in contemporary clinical practice to bridge treatment gaps and improve patient outcome.

ST-segment depression in non-ST elevation acute coronary syndromes: quantitative analysis may not provide incremental prognostic value beyond comprehensive risk stratification.

BACKGROUND: It is unclear whether quantitative ST-segment assessment can improve risk stratification of unselected acute coronary syndrome (ACS) patients using the validated Global Registry of Acute Cardiac Events (GRACE) risk model. METHODS: In the prospective, multicenter, Canadian ACS Registry, the admission electrocardiogram was evaluated centrally at a blinded core laboratory. Patients with ST-elevation myocardial infarction and other electrocardiogram confounders were excluded. ST depression (ST down) was measured and summed in all leads except aVR. Patients with ST down were divided into 3 groups based on tertiles of cumulative ST down. A multivariable model was developed to examine the independent prognostic value of ST down severity after adjusting for other known prognosticators in the GRACE risk model. RESULTS: Among 2590 patients with non-ST-elevation ACS, more severe ST down was associated with advanced age, higher heart rate and Killip class, elevated creatinine, abnormal biomarkers, higher GRACE risk score, and higher 1-year mortality (all P < .001). After adjusting for these confounding prognosticators, the presence of any ST down remained independently associated with higher 1-year mortality (odds ratio 1.78, 95% CI 1.21-2.63, P = .004). However, the gradient of risk with increasing magnitude of ST down was no longer evident (adjusted odds ratios 1.77, 1.77, 1.81, for ascending tertiles of cumulative ST down, respectively). Moreover, quantitative ST down did not improve the model discrimination for 1-year mortality. The results were similar when the number of leads with ST down or the maximum magnitude of ST down was analyzed, after adjusting for tertiles of GRACE risk score or inhospital revascularization, or using the composite end point of death or myocardial (re)infarction at 1 year. CONCLUSIONS: Greater ST down is associated with other adverse prognosticators across the broad spectrum of non-ST-elevation ACS. Although the presence of any ST down is an independent predictor of 1-year mortality, its quantitative assessment is not as important as its mere presence when studied on the background of comprehensive clinical and biomarker evaluation in a nonclinical trial-based ACS population.