Magnesium changes during hemodialysis alter the QTc interval and QTc dispersion

Abstract

The purpose of our study was to determine the QTc interval, QTc dispersion in CKD and HD patients, and to assess the effect of HD on QTc interval, QTc dispersion. Twenty-five HD and 20 CKD patients were included in the study. Serum concentrations of K+, Ca2, Mg2, creatinine, and albumin were monitored and QT interval and QT dispersion were measured from 12 lead ECG. ResultsIn 5 of the patients with CKD abnormally prolonged QTc interval was found. In addition to the prolonged QTc dispersion was detected in three patients. Among pre-HD patients, 14 patients had prolonged QT interval, and 12 had QTc dispersion. The HD patients (pre-HD and post-HD) were found to have prolonged QTc interval compared to patients with CKD (p<0.001).QTc interval increased significantly in post-HD, compared to pre-HD (p=0.007). This increase in QTc interval was not homogeneous; QTc interval increased in 16 patients, it reduced in 5 patients, in 4 patients it did not change.No significant difference in QTc dispersion was found in post-HD compared to pre-HD (p>0.05). Post-HD while QTc dispersion increased in 14 patients, remained constant in 2 patients, in the remaining 11 patients decreased.The patients with prolonged QT interval (n: 16) and QT dispersion (n: 14) in post-HD, only at the level of Mg2 significantly decreased (p<0.01). ConclusionsHD patients (pre-HD and post-HD) had an abnormally prolonged QT interval compared to CKD patients.The patients with prolonged QT interval and QT dispersion in after HD, only at the level of Mg2 significantly decreased. The low Mg level may predispose HD patients to risk factor for cardiac arrhythmias.