Reciprocal ST-segment depression in precordial leads is a common finding in acute inferior myocardial infarction. The responsible mechanism and the significance of this finding, however, are still controversial.

Clinical characteristics, serial eletrocardiograms, angiographic findings of coronary artery and left ventricle were reviewed in 33 patients with acute inferior myocardial infarction. Reciprocal ST-segment depression was defined as ST-segment depression ≥1.0mm in two or more adjacent chest leads, I and aVL in patients with acute inferior myocardial infarction showing ST-segment elevation in II, III, aVF. Coronary angiography and left ventriculography were performed 15,2±16.9 hours after arrival.

Eleven patients did not have reciprocal ST-segment depression(group A) and 22 patients had reciprocal ST-segment depression(group B). There was no significant difference in the demographic data of the patients except age and peak CK-MB, which were significantly higher in group B than group A. Left anterior descending coronary artery(LAD) stenosis was significantly more frequent in group B than group A(54.5% vs 18.2%, p<0.05). However the distribution of left ventricular regional wall motion abnormality and global ejection fraction showed no difference between two groups. In addition, there was no difference in in-hospital complications.

These results suggest that reciprocal ST-segment depression in acute inferior myocardial infarction can be explained by anterior ischemia due to concomitant LAD stenosis in some cases, but its clinical significance is limited at least in terms of in-hospital complications.