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: Physiology
[{'content': 'All are effects of sympathetic stimulation except \nSelect and explain. \nA. Increased conduction velocity, B. Increased hea rate, C. Increased refractory period, D. Increaed contractility of hea', 'role': 'user'}, {'content': "Answer: C \nExplanation: Stimulation of the sympathetic cardiac nerves speeds the depolarizating effect of IH and the rate of spontaneous discharge increasesThis is possible by decrease in the refractory period Ref: Ganong's Review of Medical Physiology Twenty-Third Edition Page No:492", 'role': 'assistant'}]