BACKGROUND: Limited data suggest that ST elevation (ST elevation) in aVR is associated with higher mortality and more extensive coronary artery disease in the setting of non-ST elevation acute coronary syndromes (ACS).

METHODS: In the prospective Global Registry of Acute Coronary Events (GRACE) electrocardiographic substudy, the admission electrocardiograms were analyzed by a blinded core laboratory. We performed multivariable analysis to determine (1) the independent prognostic significance of ST elevation in aVR and (2) its association with significant (> or = 50% stenosis) left main or 3-vessel disease (LM/3-vd).

RESULTS: Among 5064 patients with non-ST elevation ACS, 4696 had no ST elevation in aVR, 292 (5.8%) had minor (0.5-1 mm) ST elevation in aVR, and 76 (1.5%) had major (>1 mm) ST elevation in aVR; their in-hospital mortality rates were 4.2%, 6.2%, and 7.9%, respectively (P for trend =.03). At 6 months follow-up, the cumulative mortality rates were 7.6%, 12.7%, and 18.3%, respectively (log-rank P for trend <.001). However, minor and major ST elevation in aVR were not independent predictors of in-hospital or 6-month death after adjusting for other validated prognosticators in the GRACE risk model. Of the 2416 patients without prior coronary bypass surgery who underwent cardiac catheterization, the prevalence of LM/3-vd was 26.1%, 36.2%, and 55.9% for the groups with no, minor, and major ST elevation in aVR, respectively (P for trend <.001). After adjusting for other clinical characteristics, major ST elevation in aVR remained an independent predictor of LM/3-vd (adjusted odds ratio, 2.68; 95% confidence interval, 1.29-5.58; P = .008).

CONCLUSION: ST elevation in aVR is less prevalent than reported in previous smaller studies. Although it is associated with higher unadjusted in-hospital and 6-month mortality, it does not provide incremental prognostic value beyond comprehensive risk stratification using the validated GRACE risk model. However, ST elevation greater than 1 mm in aVR may be useful in the early identification of LM/3-vd in ACS patients with ST depression.