This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti-Arrhythmic, 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 Drugs of PSVT-1st choice - Adenosine2nd choice - CCBs (verapamil, diltiazem) or b-blockers.", 'role': 'assistant'}]