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 3, Subject name: Medicine
[{'content': 'Feature of Torsades de pointes is? \nSelect and explain. \nA. Normal P waves, B. Sho QRS complex, C. Prolonged QTc interval, D. Sho QTc interval', 'role': 'user'}, {'content': "Answer: C \nExplanation: Torsades de pointes/Polymorphic V. Tachycardia-Prolonged QTc interval QTc=''C'' means corrected T wave,as it does not end immediately. T wave goes in slight gradual slope, so we exactly cannot pin point end of the T wave. So to pin point end of T wave ,mathematical scenario called as QTc is used", 'role': 'assistant'}]