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': 'Desynchronised defibrillation is used in- \nSelect and explain. \nA. Atrial fibrillation, B. Atrial flutter, C. SVT, D. Ventricular fibrillation', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Synchronized electrical cardioversion is used to treat hemodynamically unstable supraventricular (or narrow complex) tachycardias, including atrial fibrillation and atrial flutter. Pulseless ventricular tachycardia and ventricular fibrillation are treated with unsynchronized shocks referred to as defibrillation. Ref Harrison 20th edition pg 1432', 'role': 'assistant'}]