The patient will have an elevated serum calcium and will show clinical manifestations of hypercalcemia.
Classic change: shortening of the QT interval (due to shortening of the duration for phase 2 of the action potential)
Additional changes that may occur:
(1) changes to the T-wave (inverted, notched, biphasic, decreased amplitude)
(2) prolonged QRS interval
(3) prolonged PR interval
(4) second or third degree atrioventricular (AV) block
(5) J wave (Osborn wave)
Reversal of the hypercalcemia should be accompanied by a correction in the ECG changes.
Differential Diagnosis:
(1) tricyclic antidepressant effect
(2) localized increase in calcium ions within the myocardium (infusion of a calcium salt, etc)
