Cell-associated magnesium and QT dispersion in hemodialysis patients

Abstract Background: Impaired magnesium (Mg) homeostasis has been implicated in a variety of cardiovascular disturbances, including ventricular arrhythmias and changes in the interval between the onset of wave Q to the end of wave T (QT interval) on electrocardiogram. Cardiac arrhythmias are common in patients on hemodialysis therapy. Methods: We investigated the relationship between QT interval corrected for heart rate (QTc) dispersion and Mg content in peripheral blood mononuclear cells (PBMC) of chronic hemodialysis patients treated with high-dose calcium carbonate providing Mg in excess (group I; n=18) or low-dose calcium carbonate and smaller Mg load (group II; n=13). Results: Mean Mg content in PBMC of group I patients (27.9 ± 4.2 [SD] μmol/L/mg protein) was significantly greater than in group II patients (10.4 ± 4.1 μmol/L/mg protein; P P P P P P P Conclusion: Prolongation of QTc dispersion in patients on chronic hemodialysis therapy could be, at least in part, a consequence of increased concentrations of c-a Mg resulting from excess daily Mg intake. Am J Kidney Dis 41:196-202. © 2003 by the National Kidney Foundation, Inc.