This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
[{'content': 'Class 3 antiarrhythmic drugs is \nSelect and explain. \nA. Amiodarone, B. Phenytoin, C. Propafenone, D. Pindolol', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Refer kDT 6/e p 511 Class III agents have the potential to prolong the QT interval of the EKG, and may be proarrhythmic (more associated with development of polymorphic VT). Class III agents include: bretylium, amiodarone, ibutilide, sotalol, dofetilide, vernakalant and dronedarone', 'role': 'assistant'}]