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: Pharmacology
[{'content': 'Digitalis has positive Inotropic effect-by the viue of its effect on: \nSelect and explain. \nA. Na+K+ ATPase pump, B. Na Glucose channels, C. H+K+ ATPase pump, D. Calcium pump', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ref:KDT 6/e p496 Digitalis is used clinically because it exes a positive inotropic effect and because it slows transmission in the AV node in patients with supraventricular tachyarrhythmias. The positive inotropic effect is due to inhibition of the sodium/potassium pump at the outer cell membrane.', 'role': 'assistant'}]