This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: ECG and Arrhythmia 2, Subject name: Medicine
[{'content': 'What is the best treatment for the new-onset atrial flutter? \nSelect and explain. \nA. Cardioversion, B. Procainamide, C. Bretylium, D. Amiodarone', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Recent-onset atrial flutter: Electrical cardioversion of low-intensity 25-50 J can conve 90% of patients into normal sinus rhythm and is most effective therapy. In atrial flutter usage of class I agents(Procainamide) will lead to the slowing of atrial flutter to a point where 1:1 conduction will occur and hea rate can jump up to 200 bpm leading to hemodynamic compromise. Ibutilide: 1 mg infusion over 60 minutes will work in 50-70% of patients reveing them to normal sinus rhythm. However, it is not given in the choices. Recurrent atrial flutter: Anti-arrhythmic drugs like sotalol, amiodarone can be used but 70% will experience recurrence. In this situation catheter ablation at cavotricuspid isthmus is more effective.', 'role': 'assistant'}]