This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiac Cycle, Subject name: Physiology
[{'content': 'Left ventricular (LV) pressure-volume loop is shown below. During exercise within physiological limits, what is the effect on end-systolic volume? \nSelect and explain. \nA. ESV decreases, B. ESV increases, C. ESV remains unchanged, D. ESV first decreases then increases', 'role': 'user'}, {'content': 'Answer: A \nExplanation: - There is increased sympathetic discharge that has a positive inotropic effect on the hea. - LV contractility increases, ejecting a greater stroke volume (SV). - Hence, there is decrease in ESV, as shown in the image.', 'role': 'assistant'}]