The effect of oral magnesium chloride therapy on the QTc and QUc intervals of the electrocardiogram.

The effect of magnesium, given orally as enteric-coated magnesium chloride tablets, on the ECG of 25 randomly selected patients was investigated. Each patient, who served as his own control, was given 4--6 tablets, each containing 0,5 g MgCl26H2O, at night for periods varying from 6 weeks to 2 years. Findings included (i) a statistically significant decrease in OTc and QUc intervals; (ii) a progressive shortening of QTc and QUc intervals with continuing therapy; (iii) reversion to normal of ECG abnormalities, especially of ST segments and T waves.