Objective: In a subgroup of patients with the anterior wall myocardial infarction (MI), the electrocardiogram (ECG) records a concomitant inferior ST-segment elevation (STE), which is generally explained by a “wrap-around” left anterior descending (LAD) artery occlusion. However, recent evidence indicates that this may be due to a distal LAD occlusion, which may be irrelevant to the LAD length. We investigated the relationship between inferior ST-T changes in anterior MI and the presence of a wrap-around LAD.
Methods: Consecutive patients diagnosed with anterior MI due to an acute LAD occlusion were enrolled into the study. All ECGs were measured manually by a cardiologist, who was blinded to the angiographic outcomes. The site of the LAD occlusion was determined using multiple angiographic views. A wrap-around LAD was defined as a LAD artery from a post-reperfusion coronary angiogram that perfused at least one-fourth of the inferior wall of the left ventricle in the right anterior oblique projection.
Results: A total of 379 anterior MI cases were enrolled, and the final study population consisted of 259 patients. The presence of a wrap-around LAD was more frequent in patients presenting with inferior STE compared with patients without inferior STE (62.1% vs. 30.4%, p=0.001), however, this relationship was weak (φ=0.211). Inferior STE was more frequent in distal occlusions (22.9% vs. 4.3%, p<0.001), which showed a stronger relationship (φ=0.285). The polarity of the T-wave in lead III did not give any clues about the LAD anatomy.
Conclusion: Contrary to the popular acceptance, our results indicate that a wrap-around LAD cannot be reliably diagnosed by ECG.