The significance of ST-elevation in aVL in anterolateral myocardial infarction: An assessment by cardiac magnetic resonance imaging

Background: Anterolateral myocardial infarction (MI) is traditionally defined on the electrocardiogram by ST-elevation (STE) in I, aVL, and the precordial leads. Traditional literature holds STE in lead aVL to be associated with occlusion proximal to the first diagonal branch of the left anterior descending coronary artery. However, concomitant ischemia of the inferior myocardium may theoretically lead to attenuation of STE in aVL. We compared segmental distribution of myocardial area at risk (MaR) in patients with and without STE in aVL. Methods: We identified patients in the MITOCARE study presenting with a first acute MI and new STE in two contiguous anterior leads from V₁ to V₆, with or without aVL STE. Patients underwent cardiac magnetic resonance imaging 3–5 days after acute infarction for quantitative assessment of MaR. Results: A total of 32 patients met inclusion criteria; 13 patients with and 19 without STE in lead aVL. MaR > 20% at the basal anterior segment was seen in 54% of patients with aVL STE, and 11% of those without (p = 0.011). MaR > 20% at the apical inferior segment was seen in 62% and 95% of patients with and without aVL STE, respectively (p = 0.029). The total MaR was not different between groups (44% ± 10% and 39% ± 8.3% respectively, p = 0.15). Conclusion: Patients with anterior STEMI and concomitant STE in aVL have less MaR in the apical inferior segment and more MaR in the basal anterior segment.