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: Anaesthesia
[{'content': 'Anaesthetic agent of choice in congenital heart disease with right to left shunt is \nSelect and explain. \nA. Thiopentone, B. Propofol, C. Etomidate, D. Ketamine', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ketamine being sympathomimetic causes raised left sided pressures, which obstructs shunt flow.', 'role': 'assistant'}]