Reciprocal ST segment changes in acute inferior myocardial infarction: clinical, haemodynamic and angiographic implications.

Reciprocal ST segment changes are frequent during acute inferior myocardial infarction, yet their significance remains controversial. In order to investigate the implications of these changes, the ECG obtained on admission for 83 patients with acute inferior myocardial infarction was compared with the clinical course and the results of angiographic and coronary arteriographic studies performed an average of 3 weeks after the onset of symptoms. Group 1 consisted of 59 patients with at least 1 mm of horizontal on downsloping ST segment depression in at least 1 of leads V to V. Group 2 consisted of 24 patients without precordial ST depression in this area. Group 1 patients were generally older than group 2 patients (59.6 ± 6.4 versus 54 ± 5.3 yr, P<0.01) had higher total creatine kinase (CK) levels and MB fractions (1835 ± 940 versus 875 ± 305, P < 001, 269 ± 102 versus 95 ± 35 for MB fraction) and more complications during the hospital course (80% versus 38% P<0.01) and greater left ventricular dysfunction (ejection fraction 52.2 ± 6% for group I versus 59.2±7% for group 2; cardiac index 2.75±0.41min m for group 1 versus 3.25 ± 0.3 lmin m for group 2 P<0.005). No difference was observed on biplane angiography as far as left ventricular wall kinesis was concerned. By contrast, coronary arteriography revealed more frequent left coronary artery disease in group 1 patients (84%) than in group 2 patients (37%) P<0.005, the left anterior descending and circumflex arteries being equally often affected. Finally, the persistence of ST segment depression for more than 48 hours was associated with a more severe depression of the ejection fraction than transient depression (less than 48 hours). In summary, the presence of ST segment depression in the precordial leads during the acute phase of inferior myocardial infarction was associated with greater myocardial necrosis and more frequent left coronary artery disease, thus identifying a subset of high risk patients. [ABSTRACT FROM PUBLISHER]