This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'All of the following used in the treatment of cardiac arrest following ventricular fibrillation , except \nSelect and explain. \nA. Atropine, B. Epinephrine, C. Antiarrhythmic agents, D. Vasopressin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ref Harrison 19 th ed pg 1768 Atropine is no longer considered effective for asystole or PEA, but can be used for bradyarrhythmias. External pacing devices are used to attempt to establish a regular rhythm when atropine fails for a bradyarrhythmia, but chronotropic agents given intravenously are now recognized as an equally effective alternative.', 'role': 'assistant'}]