title: QT Interval and QT Dispersion in Patients Undergoing Hemodialysis: Revisiting the Old Theory.
abstract: OBJECTIVE
  We sought to explore the response of the corrected QT (QTc) interval duration and QT dispersion (QTD) to hemodialysis.
  
  
  METHODS
  We enrolled 50 patients with end-stage renal disease undergoing regular hemodialysis. Blood samples were drawn for measurement of serum electrolytes, and a 12-lead ECG was performed to measure the QTc interval duration and QTD, immediately before and just after dialysis sessions.
  
  
  RESULTS
  The mean age of the cohort was 42.8 ± 12.2 years (58% males). Both the QTc duration and QTD showed marked variability after hemodialysis. A significant correlation was found between the decrease of both serum potassium and magnesium levels after dialysis and the post-dialysis QTc interval duration, with Pearson's correlation coefficients r = -0.43 and r = -0.34, p = 0.002 and p = 0.01, respectively. Patients with a post-dialysis increase of QTc interval duration had a significantly higher percentage of reduction of serum potassium (p = 0.029), whereas patients with a post-dialysis increase of QTD had a significantly higher percentage of reduction of serum magnesium (p = 0.03).
  
  
  CONCLUSIONS
  Our findings suggest a highly variable response of the QTc interval duration and QTD to hemodialysis. The post-dialysis QTc interval duration inversely correlated with the decrease of both serum potassium and magnesium levels after dialysis.
authors.affiliation: Cardiology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Alabd
authors.forename: Walid
authors.initials: W
authors.lastname: El-Hammady
authors.forename: Ahmed
authors.initials: A
authors.lastname: Shawky
authors.forename: Wail
authors.initials: W
authors.lastname: Nammas
authors.forename: Mohamed
authors.initials: M
authors.lastname: El-Tayeb