Discussion of electrocardiographic diagnostic criteria for acute posteroseptal myocardial infarction

Objective To approach the infarct sites in 4 patients with inferior wall AMI concomitant ST segment elevation in leads V_ 1-3 and V_ 3R-5R . These patients were diagnosed as inferior, right ventricular and anteroseptal walls AMI at admission. Methods Electrocardiographic data and results of isotope 99m Tc-MIBI myocardial perfusion imaging and coronary angiography were analyzed.Results Electrocardiogram showed ST segment significantly elevated in standard leads Ⅱ,Ⅲ , aVF, and leads V_ 1-3 and V_ 3R-5R , the magnitude of ST segment elevation was maximal in lead V_1. There was isotope 99m TC-MIBI myocardial perfusion defect in inferior and posteroseptal walls in these patients. Coronary angiography showed that right coronary artery was infarct-related artery. Conclusion According to data above, we put forward the diagnostic criteria for the posteroseptal wall AMI as followed: ① ST segment elevation ≥2mm in lead V_1 in the clinical setting of inferior wall AMI. ② The magnitude of ST segment elevation in leads V_ 1-3 and leads V_ 3R-5R are showed as V_1V_2V_3 and V_1V_ 3R V_ 4R .With two conditions above, inferior and posteroseptal walls AMI should be diagnosed.