Abnormal increase in the amplitude of 'U' wave is seen with

Ans. d (All of the above) (Ref. Harrison's Internal medicine, p. 1314; Topol cardiology Textbook, p. 158)'U' Wave# Occurs due to repolarisation of papillary muscles (Ganong Physiology p. 550, 22nd edition)# Normally upright (< 1 mm) or (< 10% of height of T wave)