This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Medicine
[{'content': 'Pulsus bigeminy is seen in? \nSelect and explain. \nA. Digitalis, B. Beta Blockers, C. ACE inhibitors, D. Calcium channel blockers', 'role': 'user'}, {'content': 'Answer: A \nExplanation: digoxin and digitalis causes pulses bigemini Pulsus bigeminus is a cardiovascular phenomenon characterized by groups of two heabeats close together followed by a longer pause. The second pulse is weaker than the first. Look for a pattern of what appears to be a relatively normal QRS complexes, each followed by a smaller, abnormal one . Ref Davidson 23rd edition pg 456', 'role': 'assistant'}]