ABSTRACT
BACKGROUND: 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. METHODS: 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 > or =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. RESULTS: 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(p0.05). CONCLUSION: 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.
Subject(s)
Humans , Coronary Vessels , Depression , Electrocardiography , Heart Block , Heart Failure , Incidence , Infarction , Inferior Wall Myocardial Infarction , Mortality , Myocardial Infarction , PrognosisABSTRACT
BACKGROUND: 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. METHODS: 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 > or =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. RESULTS: 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. CONCLUSIONS: 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.