Abstract 4862: ST-Segment Depression in Lead aVR: A Useful Predictor of Impaired Myocardial Reperfusion in Patients With Anterolateral ST-Segment Elevation Acute Myocardial Infarction
Background: ST-segment depression in lead aVR during ST-segment elevation acute myocardial infarction (STEMI) theoretically represents a reciprocal change in response to an opposite vector resulting from ST-segment elevation in the apical and inferolateral walls. We hypothesized that ST-segment depression in lead aVR during anterolateral STEMI is associated with less successful myocardial reperfusion, because of more extensive area at risk.
Methods: We studied 301 patients with a first anterolateral STEMI who underwent coronary recanalization (TIMI grade 3 flow) by fibrinolysis or percutaneous coronary intervention within 6 h after symptom onset. Patients were divided into the 3 groups according to ST-segment deviation in lead aVR on admission ECG: group A, 71 patients with ST-segment elevation of ≥ 0.5 mm; group B, 131 patients without ST-segment deviation; and group C, 99 patients with ST-segment depression of ≥ 0.5 mm. Myocardial blush grade was assessed immediately after recanalization.
Results: There were no differences in age, sex, coronary risk factors, time from symptom onset to admission, or multivessel disease among the 3 groups. In groups A, B, and C, the incidence of Killip class ≥ 2 was 6%, 6%, and 15% (p=0.03); the sum of ST-segment elevation in leads I, aVL, and V1– 6 was 20±11, 23±9, and 33±14 mm (p<0.01); the rates of initial TIMI grade 0 or 1 flow was 56%, 70%, and 78% (p=0.01); good collateral circulation was 43%, 39%, and 22% (p=0.03); impaired myocardial reperfusion (defined as myocardial blush grade 0 or 1) was 14%, 23%, and 65% (p<0.01); peak creatine kinase level was 3432±1995, 4045±2144, and 5986±2550 mU/ml (p<0.01); and predischarge left ventricular ejection fraction was 56±13%, 51±11%, 44±12% (p<0.01), respectively. Multivariate analysis showed that ST-segment depression in lead aVR was an independent predictor of impaired myocardial reperfusion (odds ratio 3.31, 95% CI 1.98 to 5.52, p<0.001); but sum of ST-segment elevation in leads I, aVL, and V1– 6 was not.
Conclusions: In patients with anterolateral STEMI, ST-segment depression in lead aVR on admission ECG is associated with less successful myocardial reperfusion and larger infarct. Assessment of ST-segment deviation in lead aVR is useful for acute risk stratification.