Inferior myocardial infarctions account for 40-50% of all acute myocardial infarctions and are generally viewed as having a more favorable prognosis than anterior wall infarctions. However, nearly 50% of patients suffering inferior infarction will have complications such as heart block, concomitant precordial ST-segment depression and right ventricular infarction or distinguishing features associated with an increased mortality that will substantially alter an otherwise favorable prognosis.

Clinical characteristics, electrocardiograms, and angiographic findings of coronary artery were viewed in 47 patients with inferior myocardial infarction. Significant ST-segment change was defined as ≥0.1mV horizontal or down sloping depression in acute inferior myocardial infarction patients with ST-segment elevation on leads II, III, aVF measured with reference to the TP segment, 80ms after J point.

A group=no precordial ST-segment depression.

B group=sum of ST-segment depression in leads V₁ to V₃ equal to or more than the sum of ST-segment depression in leads V₄ to V₆.

C group=maximal precordial ST-segment depression in leads V₄ to V₆.

1) Incidence of multi-vessel disease in group A and in group B were 23% and 22%, respectively, compared with 60% for those of group C(p<0.05).

2) Incidence of Killip class III and IV rates in patients with group A and B were 8% and 12%, respectivly, compared with 47% for those patients with group C(p<0.05).

3) No significant difference of sex, age, peak CK level were found among three groups(p>0.05).

The patients with acute inferior myocardial infarction with the maximal ST-segment depression in leads V₄ to V₆ would be at high risk for congestive heart failure and multi-vessel disease.