This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Medicine
True about U waves is all except 
Select and explain. 
A. It is due to Delayed repolarisation of Purkinje fibres, B. Maximum normal amplitude of the U wave is 1-2 mm, C. The U wave normally goes in the opposite direction as the T wave, D. U waves generally become visible when the hea rate falls below 65 bpm
C: The U wave normally goes in the opposite direction as the T wave
Answer: C: The U wave normally goes in the opposite direction as the T wave 
Explanation: The U wave normally goes in the same direction as the T waveU -wave size is inversely propoional to hea rate: the U wave grows bigger as the hea rate slows downU waves generally become visible when the hea rate falls below 65 bpm