Snapshot A 70-year-old man presents to the emergency room with chest pain for the past hour. He has a medical history of coronary artery disease, hyperlipidemia, and type 2 diabetes mellitus. He has a 30-pack-year smoking history and drinks alcohol regularly. His electrocardiogram reveals ST-segment elevations in leads V3 and V4. Aspirin is given and he is rushed for an angioplasty. (Myocardial infarction with left main coronary artery involvement) Anatomy Coronary arteries include login to view 25 more bullets Coronary arterial system dominance login to view 10 more bullets Coronary sinus login to view 4 more bullets Left atrium login to view 4 more bullets Localization of Myocardial Infarctions (MI) Leads with ST-Segment Elevation Location of MI Vessel(s) Affected V1-V2 Septal LAD V3-V4 Anterior LAD V5-V6 Apical LAD, LCX, or RCA I and aVL Lateral LCX V7-V9 Posterior RCA and LCX II, III, and aVF Inferior RCA and LCX Pathology Coronary steal phenomenon login to view 7 more bullets