This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Medicine
[{'content': 'Posterior wall MI not present \nSelect and explain. \nA. ST elevation in V1-V3 leads, B. Tall and broad R waves, C. Tall T waves, D. Significant R waves', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (A) ST elevation in V1-V3 leads# As the posterior myocardium is not directly visualised by the standard 12-lead ECG, reciprocal changes of STEMI are souht in the anteroseptal leads V1-3.> Posterior Mi is suggested by the following changes in V1-3: Horizontal ST depression Tall, broad R waves (>30ms) Upright T waves Dominant R wave (R/S ratio > 1) in V2.> In patients presenting with ischaemic symptoms, horizontal ST depression in the anteroseptal leads (V1-3) should raise the suspicion of posterior Ml. Typical appearance of posterior infarction in V2.', 'role': 'assistant'}]