ST SEGMENT DEPRESSION IN AVL - A SENSITIVE MARKER FOR ACUTE INFERIOR MYOCARDIAL-INFARCTION

In a substantial percentage of patients with acute myocardial infarction, especially in those with inferior wall involvement, no ST elevation is detected on the electrocardiogram. In many of them, ST depression is found in leads oriented to remote segments of the heart. The importance of those reciprocal changes for early diagnosis of acute inferior myocardial infarction in patients without ST elevation has not been stressed. In order to find the prevalence of reciprocal ST depression, we evaluated the admission electrocardiograms of 107 consecutive patients with evolving first acute inferior mvocardial infarction. Ninety-three patients had ST elevation of at least 0.1 mV in at least one of the inferior leads: II, III or a VF (group A) and in 14 patients ST displacement did not reach 0·1 mV in any of these leads (group B). In both groups, reciprocal ST depression occurred more frequently in a VL than in any other lead. Only three patients had no ST depression in a VL. in eight patients (7·5% ST depression in a VL was the sole early electrocardiographic sign of the inferior infarction, a VL is the only lead that is facing the superior part of the left ventricle and thus is the only lead that is truly opponent to the inferior wall. It seems that ST depression in a VL, by contrast to that in the precordial leads, is found in the majority of patients with evolving inferior wall myocardial infarction and is not influenced by extension of the infarclion to the right ventricle or to the posterior wall. We conclude that transient ST depression in a VL is a sensitive early electrocardiographic sign of acute inferior wall myocardial infarction. © 1993 The European Society of Cardiology.