Electrocardiographic characteristics of posterior myocardial infarction in comparison to angiographic findings

BACKGROUND Myocardial infarction (MI) is a cardiac cell death following the imbalance of supply and demand. Electrocardiography (ECG) is a diagnostic test for MI and can help the clinicians to estimate the severity and size of infarction, to suggest the artery related to the infarct and localize the pathology. The aim of this study is to evaluate the diagnostic value of ECG in posterior MI (PMI) compared with angiographic findings. METHODS In a prospective observational study, using simple sampling patients with diagnosis of PMI (ST elevation in at least two consecutive leads V7, V8, and V9) were enrolled and all standard 12 leads and also V7, V8, V9 and right leads, including V3R and V4R were recorded and angiography was performed. ECG changes were recorded and compared with angiography findings. RESULTS In this study, totally 138 patients were enrolled (mean ± standard deviation age of 65.00 ± 12.97 and 76.8% male). Left circumflex artery (LCX), right coronary artery (RCA) and left anterior descending artery (LAD) occlusions occurred in 65.9, 50.7, and 29 percent respectively. Patients with LCX occlusion had a significantly higher frequency of ST elevation in V5, V6, I and AVL (P ≤ 0.001). Patients with RCA occlusion had a significantly higher frequency of ST elevation in V1, V3R, and V4R and also ST depression in V5 and V6 (P ≤ 0.001). CONCLUSION In PMI, there is a relationship between ECG findings and different coronary artery occlusions. Hence that ECG is a useful tool to predict the LCX or RCA occlusion in PMI.