Background: The correlation between ST-segment elevation (ST upward arrow) in lead V(3)R (ST upward arrow(V3R)), lead V(1) (ST upward arrow(V1)), and lead aVR (ST upward arrow(aVR)) during anterior wall acute myocardial infarction (AMI) and the culprit lesion site in the left anterior descending (LAD) coronary artery and the nature of the conal branch of the right coronary artery has not been thoroughly described.
Methods: One hundred forty-two patients with first anterior wall AMI were included. The 15-lead electrocardiogram with the standard 12 leads plus leads V(3)R through V(5)R showing the most pronounced ST-segment deviation before initiation of reperfusion therapy was evaluated and correlated with the exact LAD occlusion site in relation to the first septal perforator (S1) and the nature of the conal branch of the right coronary artery as determined by coronary angiography.
Results: ST-segment elevation in lead aVR, ST upward arrow(V1) of at least 2 mm, and ST upward arrow(V3R) of at least 1 mm were more prevalent among patients with occlusions proximal to S1 than patients with occlusions distal to S1 (41.7% vs 4.9%, P < .01; 30.0% vs 7.3%, P < .01; and 91.7% vs 4.9%, P < .01, respectively). Of the 60 patients with occlusions proximal to S1, 20 patients had a small conal branch (18 patients with ST upward arrow(aVR) and 15 patients with ST upward arrow(V1) >or=2 mm), and 24 patients had a large conal branch (all patients with non-ST upward arrow(aVR) and ST upward arrow(V1) <2 mm; P < .01). The sensitivity of ST upward arrow(V1) of more than 1 mm, of at least 2 mm, ST upward arrow(V3R) of at least 1.5 mm, and ST upward arrow(aVR) for detecting a small conal branch was 65.1%, 81.8%, 84.0%, and 90%, respectively; the specificity was 68.5%, 64%, 66.7%, and 64.9%, respectively.
Conclusions: In patients with anterior wall AMI, ST upward arrow(V3R) of at least 1 mm combined with ST upward arrow in leads V(2) through V(4) were strongly predictive of LAD occlusion proximal to S1; furthermore, ST upward arrow(aVR) and ST upward arrow(V1) of at least 2 mm were found to be useful in identifying LAD occlusion proximal to S1. ST upward arrow(aVR), ST upward arrow(V3R) of at least 1.5 mm, and ST upward arrow(V1) of at least 2.0 mm were also associated with the presence of a small conal branch not reaching the intraventricular septum during anterior wall AMI.