<prompt> True about U waves is all exceptIt is due to Delayed repolarisation of Purkinje fibresMaximum normal amplitude of the U wave is 1-2 mmThe U wave normally goes in the opposite direction as the T waveU waves generally become visible when the hea rate falls below 65 bpm  <response>: 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 