<prompt> All are ECG changes hypokalemia,except-U waveST segment saggingT-wave flattening or inversionQT interval prolongation  <response>: Multiple medications, electrolyte abnormalities hypocalcemia, hypomagnesemia and hypokalemia and ceain disease states ie, intracranial hemorrhage can prolong the QT interval. Prolonged QT genetic syndromes exist and include Romano-Ward syndrome, Jervell-Lange-Nielsen syndrome and long-QT syndrome. Ref Harrison 20th edition pg 1445 