title: Frequent nocturnal hemodialysis associates with improvement of prolonged QTc intervals.
abstract: OBJECTIVE
  Sudden cardiac death remains the leading cause of death in hemodialysis (HD) patients. Prolongation of QTc intervals (as measured by the tangent method) increases sudden cardiac death risk in populations without kidney disease.
  
  
  METHODS
  We performed a retrospective electrocardiograph (ECG) and chart review of HD patients. Our objectives were (1) to establish the effect of one of four different dialysis modalities on interdialytic QTc intervals, (2) to determine the effect of dialysis frequency and time on QTc interval and on the prevalence of borderline or prolonged QTc intervals, and (3) to determine if changes in QTc interval were simultaneous to changes in electrocardiographic left ventricular mass.
  
  
  RESULTS
  Frequent nocturnal HD was associated with a decrease in QTc interval for all patients (from 436.5 to 421.3 ms, p = 0.0187) and for patients who initiated dialysis with prolonged QTc (468.2 to 438.2 ms, p = 0.0134). This change happened before changes in left ventricular mass were evident. Dialysis duration predicted a decrease in QTc better than dialysis frequency (R(2) 6.50 vs. 3.00%, p = 0.023 vs. 0.102). Prevalence of borderline or prolonged QTc increased in patients dialyzed <4 h/session (12/39 to 22/39, p = 0.039).
  
  
  CONCLUSIONS
  Frequent nocturnal HD may be the ideal modality to initiate HD in end-stage kidney disease patients with prolonged QTc.
authors.affiliation: Division of Nephrology, Department of Medicine, London Health Sciences Centre and Western University, London, Ont., Canada.
authors.forename: Benjamin K A
authors.initials: BK
authors.lastname: Thomson
authors.forename: Bogdan
authors.initials: B
authors.lastname: Momciu
authors.forename: Shih-Han S
authors.initials: SH
authors.lastname: Huang
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Chan
authors.forename: Brad L
authors.initials: BL
authors.lastname: Urquhart
authors.forename: Allan C
authors.initials: AC
authors.lastname: Skanes
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Krahn
authors.forename: George J
authors.initials: GJ
authors.lastname: Klein
authors.forename: Robert M
authors.initials: RM
authors.lastname: Lindsay
mesh_terms: D000328:Adult; D015897:Comorbidity; D004562:Electrocardiography / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008133:Long QT Syndrome / Q000453:epidemiology* / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D006435:Renal Dialysis / Q000401:mortality* / Q000706:statistics & numerical data*; D051436:Renal Insufficiency, Chronic / Q000401:mortality* / Q000534:rehabilitation*; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate; D016896:Treatment Outcome