This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': 'The ECG in hyperkalemia classically shows:September 2009, 2010 \nSelect and explain. \nA. Increase QRS duration, B. Shoened PR interval, C. Prominent U waves, D. Increased R wave amplitude', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A: Increase QRS duration', 'role': 'assistant'}]