Abstract 8952: ST-Segment Depression in Lead aVR Predicts In-Hospital Adverse Outcomes in Patients With Inferior Wall Acute Myocardial Infarction

Abstract

Introduction: During inferior wall acute myocardial infarction (IWMI), lead aVR is frequently ignored. However, ST-segment depression in lead aVR (ST↓aVR) during IWMI might represent a reciprocal change in response to an opposite vector resulting from ST-segment elevation in the apical region, suggesting a larger area at risk. Hypothesis: We assessed the hypothesis that ST↓aVR can provide important prognostic information in patients with reperfused IWMI. Methods: We studied 268 patients with a first IWMI who had TIMI 3 flow of the right coronary artery or left circumflex coronary artery after fibrinolysis or primary percutaneous coronary intervention within 6 h after symptom onset. Patients were divided into the 3 groups according to the degree of ST↓aVR on admission ECG: G-A, 122 patients with no ST↓aVR; G-B, 95 patients with ST↓aVR ≤1.0 mm; and G-C, 51 patients with ST↓aVR >1.0 mm. The perfusion territory of the culprit artery was assessed on the basis of the angiographic distribution score. Impaired myocardial reperfusion was defined as myocardial blush grade 0/1 on the final angiogram. Results: There were no differences in age, coronary risk factors, time to admission, reperfusion therapy, culprit artery, or final TIMI flow grade among the 3 groups. In G-A, G-B, and G-C, the sum of ST-segment elevation in leads II, III, aVF and V5-6 on admission ECG was 4±4, 9±5, and 17±7 mm (p<0.01); the angiographic distribution score was 0.5±0.2, 0.6±0.2, and 0.7±0.1 (p<0.01); peak creatine kinase level was 2225±1515, 3150±1792, and 4911±2238 mU/ml (p<0.01); and the frequencies of impaired myocardial reperfusion was 4%, 18%, and 71% (p<0.01); the combined outcome of in-hospital death, reinfarction, or congestive heart failure was 2%, 7%, and 14% (p<0.01), respectively. Multivariate analysis showed that as compared with no ST↓aVR, the odds ratios (95% CI) for in-hospital adverse events associated with ST↓aVR ≤1.0 mm and ST↓aVR >1.0 mm were 1.49 (0.64-3.39; p=0.15) and 2.01 (1.18-4.51; p<0.05), respectively. Conclusions: In patients with reperfused IWMI, greater ST↓aVR on admission ECG is associated with a larger area at risk, impaired myocardial reperfusion, and a larger infarct size. ST↓aVR >1.0 mm is an independent predictor of in-hospital adverse outcomes.