This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'Drug of choice of paroxysmal supraventricular tachycardia is ? \nSelect and explain. \nA. Adenosine, B. Digitalis, C. Procainamide, D. Mexiletine', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Adenosine Treatment of paroxysmal supraventricular tachycardia Valsalva maneuver, carotid sinus massage - T vagal discharge - AV node conduction & T refractoriness. Adenosine CCBs b-blockers Adenosine is prefered because of very sho duration of action and lack of negative ionotropic effect. Prevention of PSVT - Drugs that slow conduction in the antegrade slow pathway, e.g. - Digitalis, P-blockers, CCBs.", 'role': 'assistant'}]