title: Cardiac repolarization abnormalities among patients with various stages of chronic kidney disease.
abstract: BACKGROUND
  Patients with chronic kidney disease (CKD) are at increased risk of life-threatening cardiovascular arrhythmias. Although these arrhythmias are usually secondary to structural heart diseases that are commonly associated with CKD, a significant proportion of cases with sudden cardiac death have no obvious structural heart disease. This study aims to explore the relationship of cardiac repolarization in patients with CKD and worsening kidney function.
  
  
  OBJECTIVE
  There is cardiac repolarization abnormalities among patients with chronic kidney disease.
  
  
  METHODS
  This was a retrospective, chart-review study of admissions or clinic visits to a university hospital between 2005 and 2010 by patients with a diagnosis of CKD. Inclusion criteria selected patients who had 12-lead surface electrocardiography (ECG), renal function tests within 24 hours, and transthoracic echocardiography within 6 months. Cases with a documented etiology for the corrected Qt (Qtc) interval prolongation including structural heart disease, QT prolonging drugs, or relevant disease conditions, were excluded.
  
  
  RESULTS
  Our sample size was 154 ECGs. Two-thirds of patients with CKD had QTc interval prolongation, and about 20% had a QTc interval >500 ms. QTc interval was significantly different and increased with each successive stage of CKD using the Bazett (P < 0.006) or Fridericia (P = 0.03) formula. QTc interval correlated significantly with serum creatinine (P = 0.01). These finding were independent of age, gender, potassium, and calcium concentrations.
  
  
  CONCLUSIONS
  The progression of CKD resulted in a significant delay of cardiac repolarization, independent of other risk factors. This effect may potentially increase the risk of sudden cardiac death, and may also increase the susceptibility of drug-induced arrhythmia.
authors.affiliation: Department of Geriatrics, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.
authors.forename: Khaled A
authors.initials: KA
authors.lastname: Sherif
authors.forename: Elsayed
authors.initials: E
authors.lastname: Abo-Salem
authors.forename: Ragesh
authors.initials: R
authors.lastname: Panikkath
authors.forename: Musab
authors.initials: M
authors.lastname: Nusrat
authors.forename: Meryem
authors.initials: M
authors.lastname: Tuncel
mesh_terms: D000200:Action Potentials; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D018450:Disease Progression; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006785:Hospitals, University; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D008133:Long QT Syndrome / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D051436:Renal Insufficiency, Chronic / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors