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:: (A) Decreased appetite, (B) Increased cardiac contractility, (C) Increased PR interval on the ECG, (D) Tachycardia
Answer is C. 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.