Clinical Significance of ST Segment Elevation in Posterior Leads V7, V8 and V9 in Patients with Acute Inferior Wall Myocardial Infarction

ECG diagnosis of a posterior wall myocardial infarction is difficult to diagnose through the standard 12 lead ECG, especially in the acute stage. The posterior wall MI may occur as an isolated event or often associated with an inferior wall myocardial infarction Posterior leads V7, V8 and V9 are usually ignored but it is suggested that these leads can provide ECG information that is useful for characterization of inferior AMI and diagnosis of posterior wall MI [1,2]. 15 or 18 leads ECG should be performed to correctly diagnose culprit artery in inferior wall MI. ST elevation in inferior and posterior leads (V7, V8 and V9) is usually associated with occlusion of the left circumflex artery with the involvement of large infarct zone and complications [3,4]. ECG detection of posterior infarction is associated with concomitant ST depression in leads V1 to V3. However these changes are neither sensitive nor specific [5-7].