QT interval is shoens in
Hypocalcemia typically prolongs the QT interval (ST poion), whereas hypercalcemia shoens it . Digitalis glycosides also shoen the QT interval, often with a characteristic "scooping" of the ST-T-wave complex (digitalis effect). Ref Harrison 20th edition pg 1567
Hypocalcaemia
Hypokalemia
Hypercalcaemia
Hyperkalemia
C.V.S