Chen Y, et al. - In the north-eastern Chinese rural general population, authors explored the relationships between serum electrolytes and QT interval corrected (QTc) prolongation. The important risk factors for QTc prolongation were a decrease in serum potassium and an increase in serum magnesium in this population, even with normal range. Findings suggested a significant inverse association of serum potassium and QTc interval. The risk of QTc prolongation was increased by the higher serum magnesium, which was significant only in the male population.