Study objective: During inferior acute myocardial infarction (AMI), the ECG lead aVR is frequently ignored, and therefore its clinical significance remains unclear. We examined the relation between ST-segment deviation seen in lead aVR on ECGs obtained at hospital admission and myocardial reperfusion in patients who have experienced recanalized inferior AMIs.
Design and setting: Retrospective study.
Patients: A total of 225 patients with inferior AMIs in whom Thrombolysis in Myocardial Infarction grade 3 flow was achieved within 6 h after symptom onset.
Measurements and results: Patients were classified as follows according to ST-segment deviation in lead aVR on an ECG obtained at hospital admission: group A, 103 patients with no ST-segment depression; group B, 80 patients with ST-segment depression of ≤ 1.0 mm; and group C, 42 patients with ST-segment depression of > 1.0 mm. There were no differences in time from symptom onset to hospital admission or in the culprit lesion among the three groups. The degree of ST-segment elevation in leads II, III, aVF, V5, or V6, the degree of ST-segment depression in leads V1 to V4, and the sum of ST-segment deviation in these leads were lowest in group A and highest in group C. In groups A, B, and C, the incidence of impaired myocardial reperfusion, defined as myocardial blush grade 0/1, was 2%, 23%, and 67%, respectively (p < 0.001). The sensitivity and negative predictive values of ST-segment depression in lead aVR for impaired myocardial reperfusion were higher than those based on other ECG variables. Multivariate analysis showed that the degree of ST-segment depression in lead aVR was an independent predictor of impaired myocardial reperfusion (odds ratio 8.41; 95% confidence interval, 2.96 to 23.9; p < 0.001).
Conclusions: We conclude that the degree of ST-segment depression in lead aVR is a useful predictor of impaired myocardial reperfusion in patients who have experienced inferior AMIs.