title: QT and JT dispersion and cardiac performance in children with neonatal Bartter syndrome: a pilot study.
abstract: BACKGROUND
  QT dispersion and JT dispersion are simple noninvasive arrhythmogenic markers that can be used to assess the homogeneity of cardiac repolarization. The aim of this study was to assess QT and JT dispersion and their relation with left ventricular systolic and diastolic functions in children with Bartter syndrome (BS).
  
  
  METHODS
  Nine neonatal patients with BS (median age 9.7 years) and 20 controls (median age 8 years) were investigated at rest. Both study and control subjects underwent electrocardiography (ECG) in which the interval between two R waves and QT intervals, corrected QT, QT dispersion, corrected QT dispersion, JT, corrected JT, JT dispersion and corrected JT dispersion were measured with 12-lead ECG. Two-dimensional, Doppler echocardiographic examinations were performed.
  
  
  RESULTS
  Patients and controls did not differ for gender and for serum levels of potassium, magnesium, and calcium (p > 0.05). Both study and control subjects had normal echocardiographic examination and baseline myocardial performance indexes. The QT dispersion and JT dispersion were significantly prolonged in patients with BS compared to those of the controls {37.5 ms [interquartile range (IQR) 32.5-40] vs. 25.5 ms (IQR 20-30), respectively, p = 0.014 and 37.5 ms (IQR 27.5-40) vs. 22.5 ms (IQR 20-30), respectively, p = 0.003}.
  
  
  CONCLUSIONS
  Elevated QT and JT dispersion during asymptomatic and normokalemic periods may be risk factors for the development of cardiac complications and arrhythmias in children with BS. In these patients the need for systematic cardiac screening and management protocol is extremely important for effective prevention.
authors.affiliation: Department of Pediatric Nephrology and Rheumatology, Hacettepe University Faculty of Medicine, 06100 Ankara, Turkey.
authors.forename: Duygu Ovunc
authors.initials: DO
authors.lastname: Hacihamdioglu
authors.forename: Kursat
authors.initials: K
authors.lastname: Fidanci
authors.forename: Ayhan
authors.initials: A
authors.lastname: Kilic
authors.forename: Faysal
authors.initials: F
authors.lastname: Gok
authors.forename: Rezan
authors.initials: R
authors.lastname: Topaloglu
mesh_terms: D000200:Action Potentials; D000293:Adolescent; D001145:Arrhythmias, Cardiac / Q000097:blood / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D001477:Bartter Syndrome / Q000097:blood / Q000150:complications* / Q000175:diagnosis; D015415:Biomarkers / Q000097:blood; D002118:Calcium / Q000097:blood; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003971:Diastole; D015150:Echocardiography, Doppler; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D007231:Infant, Newborn; D008274:Magnesium / Q000097:blood; D008297:Male; D010865:Pilot Projects; D011188:Potassium / Q000097:blood; D011237:Predictive Value of Tests; D012307:Risk Factors; D013599:Systole; D016277:Ventricular Function, Left
chemical_list: D015415:Biomarkers; D008274:Magnesium; D011188:Potassium; D002118:Calcium