This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiac Output, Subject name: Physiology
[{'content': 'Which one of the following will decrease with an increase in ejection fraction? \nSelect and explain. \nA. Stroke volume, B. Hea rate, C. Cardiac output, D. End-systolic volume (ESV)', 'role': 'user'}, {'content': 'Answer: D \nExplanation: EF = X 100. If ejection fraction has increased, it means stroke volume has increased (or decrease in EDV, or both). If SV has increased, with a normal EDV, it means there is an increase in myocardial contractility. It will increase the cardiac output. Hea rate may or may not change. If SV has increased, then end-systolic volume will decrease.', 'role': 'assistant'}]