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Significance of reciprocal S-T segment depression in anterior precordial leads in acute inferior myocardial infarction: Concomitant left anterior descending coronary artery disease?

1981; Elsevier BV; Volume: 48; Issue: 6 Linguagem: Inglês

10.1016/0002-9149(81)90312-x

1879-1913

Juan R. Salcedo, Michael G. Baird, R. Jane Chambers, Donald S. Beanlands,

Hemodynamic Monitoring and Therapy

The reciprocal changes of S-T segment depression in the anterior precordial leads of the electrocardiogram in acute inferior myocardial infarction may be due to left anterior descending coronary artery disease and anterior wall ischemia. The electrocardiograms of 45 patients with acute inferior infarction who had subsequent cardiac catheterization (41 patients) or necropsy (4 patients) were examined to test this hypothesis. Significant left anterior descending coronary artery disease (greater than 70 percent stenosis of luminal diameter) was observed in 31 (69 percent) of the 45 patients. The sensitivity, specificity and predictive value of S-T depression (1 mm or greater) in various anterior precordial leads singly or in combination was determined for this lesion. Left anterior descending coronary artery disease was present in 23 of 24 patients with S-T depression in one or more leads from V1 to V4 (predictive value 95 percent), and this index had the best combination of sensitivity (74 percent), specificity (93 percent) and predictive value in this group. Seven of 13 patients with left anterior descending coronary artery disease had S-T depression only in lead I or aVL, or both (sensitivity 100 percent, specificity 53 percent and predictive value 54 percent). S-T depression in any of leads I, aVL and V1 to V6 occurred in 37 patients, and 31 of these had left anterior descending coronary artery disease (sensitivity 100 percent, specificity 57 percent and predictive value 84 percent). The eight patients without anterior precordial lead S-T depression did not have left anterior descending coronary artery disease. Complications of infarction developed in 13 patients;S-T depression in at least one of leads V1 to V4 occurred in 12 (92 percent) of these 13 but in only 12 (38 percent) of 32 patients without complications. Thus the predictive value of S-T depression in leads V1 to V4 (95 percent) for left anterior descending coronary artery disease is greater than the occurrence of the latter (69 percent) in all cases of acute inferior myocardial infarction (p < 0.05). S-T depression in these leads may be due not to reciprocal changes but rather to left anterior descending coronary artery disease with anterior wall ischemia. Such S-T depression is a sensitive marker for complications in these patients.