Acute anterior wall myocardial infarction entailing ST-segment elevation in lead V3R, V1 or aVR: electrocardiographic and angiographic correlations

Background

The correlation between ST-segment elevation (ST↑) in lead V₃R (ST↑_V3R), lead V₁ (ST↑_V1), and lead aVR (ST↑_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 throughly 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 V₃R through V₅R 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↑_V1 of at least 2 mm, and ST↑_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↑_aVR and 15 patients with ST↑_V1 ≥2 mm), and 24 patients had a large conal branch (all patients with non-ST↑_aVR and ST↑_V1 <2 mm; P < .01). The sensitivity of ST↑_V1 of more than 1 mm, of at least 2 mm, ST↑_V3R of at least 1.5 mm, and ST↑_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↑_V3R of at least 1 mm combined with ST↑ in leads V₂ through V₄ were strongly predictive of LAD occlusion proximal to S1; furthermore, ST↑_aVR and ST↑_V1 of at least 2 mm were found to be useful in identifying LAD occlusion proximal to S1. ST↑_aVR, ST↑_V3R of at least 1.5 mm, and ST↑_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.