QT interval is shoens in: (A) Hypocalcaemia, (B) Hypokalemia, (C) Hypercalcaemia, (D) Hyperkalemia
Answer is C. 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