Anterior S-T changes during acute inferior myocardial infarction

We investigated the clinical course of 57 patients with acute inferior myocardial infarction as regards anterior S-T segment depression. Thirty of them showed S-T segment depression greater than or equal to 0.15 mV in at least 2 precordial leads, and 27 did not exhibit such changes. Twenty-seven patients underwent post-infarction exercise stress test. Furthermore, coronary arteriographic findings and left ventricular performance were evaluated in 8 of these patients with and in 8 without anterior S-T segment depression. Patients with anterior S-T segment depression showed greater inferior S-T segment elevation on admission ECG and deeper Q wave in lead aVF in ECG tracings recorded 1 month later. Higher incidences of in-hospital angina (10/30 vs 2/27, P = 0.01) and of late development of cardiac failure (5/21 vs 0/19, P = 0.03) were found among patients with anterior S-T segment depression. They showed a higher overall coronary score (82.4 +/- 31.0 vs 32.5 +/- 28.9, P = 0.002) and left anterior descending artery score (44.1 +/- 20.7 vs 8.5 +/- 16.1, P = 0.0009) and a reduced ventricular performance, evaluated by ventriculography score (49.5 +/- 2.7 vs 51.8 +/- 2.4, P = 0.05). A higher incidence of mitral regurgitation, secondary to papillary muscle dysfunction, was also found among patients with anterior S-T segment depression (4/8 vs 0/8, P = 0.04). Furthermore, the degree of anterior S-T segment depression in each of these subjects was closely correlated with the corresponding difference from normal ventricular score (r = 0.86, P less than 0.01). Finally, no difference between the two groups of patients was found as to incidence of positive exercise stress tests.