Tag Archives: Posterior Myocardial Infarction

Introduction An acute myocardial infarction causes a number of electrocardiogram (ECG) changes corresponding to coronary anatomy.1,2 The posterior myocardial infarction (PMI) refers to an infarction of the posterior wall of the left ventricle (LV).3 On the 12-lead ECG, the key to detecting a PMI is through indirect evidence via ST-depression in the antero-septal (V1–V4) leads and evolving R-waves in V1 or V2 with R/S ratios >1.1 A common theory is that these evolving R-waves represent inverted Q-waves. While ST-depression typically occurs in V1–V4, it may also extend into V5 and perhaps other leads.4 In these cases, posterior occlusion