Maximal precordial ST-segment depression in leads V4–V6 in patients with inferior wall acute myocardial infarction indicates coronary artery disease involving the left anterior descending coronary artery system

Background: In inferior wall acute myocardial infarction, maximal ST-segment depression in left precordial leads (V4–V6) has been shown to be associated with increased in-hospital mortality, presumably due to coronary artery disease involving the left anterior descending coronary artery system. Methods: We measured ST-segment deviation from baseline in the initial electrocardiogram of patients with inferior wall acute myocardial infarction, who subsequently underwent coronary angiography during their in-hospital stay. Patients were divided into three groups: (I) No precordial ST-segment depression (n=34). (II) Maximal precordial ST-segment depression in leads V1–V3 (n=44). (III) Maximal precordial ST-segment depression in leads V4–V6 (n=14). Results: The left anterior descending coronary artery or its diagonal branch were stenosed (>50%) in 32%, 41%, and 71% of patients in groups I, II, and III, respectively (p=0.04), and severely stenosed (>70%) in 18%, 18% and 57% of patients in the respective groups (p=0.007). Conclusion: In patients with inferior wall acute myocardial infarction, maximal precordial ST-segment depression in leads V4–V6 is suggestive of severe coronary artery disease involving the left anterior descending coronary artery or its diagonal branch.