This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hematology and CVS, Subject name: Pharmacology
[{'content': 'A patient has been taking digoxin for several years and is about to receive atropine for some other indication. A common side effect of digoxin that can be blocked by atropine is: \nSelect and explain. \nA. Decreased appetite, B. Increased cardiac contractility, C. Increased PR interval on the ECG, D. Tachycardia', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Digitalis possesses vago-mimetic action - due to alteration in haemodynamics and direct CNS effects altering sympathetic activity, causes bradycardia and decreased A-V conduction (ECG as increased PR interval). Atropine can block this adverse effect and it shows || PR interval and increases HR.', 'role': 'assistant'}]