This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S., Subject name: Medicine
[{'content': 'A 69-year-old woman being treated for dysrhythmias with quinidineFor the above patient on a specific medication, select the most likely side effects to occur. \nSelect and explain. \nA. sensory loss, B. prolonged QT interval, C. Parkinsonism-like symptoms, D. action tremor', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The slowed repolarization can result in a prolonged QT interval. Life-threatening polymorphic ventricular tachycardias (torsades de pointes) can be provoked by quinidine. It is rarely used in modern practice. The increased refractory period accounts for the effect on tachycardia. Similar effects are seen with procainamide.', 'role': 'assistant'}]