title: The T wave as a marker of dispersion of ventricular repolarization in premature infants before and while on treatment with the I(Kr) channel blocker cisapride.
abstract: OBJECTIVE
  Measurement of electrocardiographic intervals to assess dispersion in ventricular repolarization may be helpful in the assessment of the risk of ventricular arrhythmia. We measured QTc, QT dispersion, and T wave intervals in premature infants before and while on treatment with the I(Kr) blocker cisapride as markers for dispersion in ventricular repolarization.
  
  
  RESULTS
  We enrolled 15 non-ventilated premature infants with a mean gestational age of 30.5 weeks, ranging from 26.5 to 33.5 weeks, and mean postnatal age of 24 days, with a range from 5 to 51 days. A digital 12 lead electrocardiogram was recorded prior to and 3 days after administering cisapride at a dose of 0.8 mg/kg/day. Serum electrolytes were simultaneously measured. Electrocardiographic measurements before and after included: QT, QTc Bazett, QT dispersion, R-R, T wave interval peak to end, T wave interval peak to end/onset Q to T wave peak, T wave axis, T wave maximum voltage and QRS-T angle. A paired t test and analysis of variance was used to compare the variables before and during treatment. The QTc, T wave interval peak to end and the ratio T wave interval peak to end/onset Q to T peak increased significantly following treatment with cisapride. Results expressed as before and during treatment were for QTc: 429 (65) ms versus 454 (29) ms p < 0.02; for T wave interval peak to end: 65 (11) ms versus 103 (24) p <0.01, for the ratio T wave interval peak to end/onset Q to T peak: 0.32 (0.06) versus 0.55 (0.16) p < 0.001. Treatment with the I(Kr) blocker did not significantly alter the QT dispersion, T wave voltage, angle or QRS-T angle.
  
  
  CONCLUSIONS
  The interval from the peak to the end of the T wave and the ratio of this value to the onset Q to T peak interval, represents regional dispersion of repolarization across the ventricular wall. This is a potentially useful clinical index in the assessment of arrhythmic risk in premature infants being treated by blockade of the I(Kr) channels.
authors.affiliation: Department of Pediatric Cardiology, Academic Hospital, Free University of Brussels, Belgium. Abraham.Benatar@az.vub.ac.be
authors.forename: Avram
authors.initials: A
authors.lastname: Benatar
authors.forename: Filip
authors.initials: F
authors.lastname: Cools
authors.forename: Tine
authors.initials: T
authors.lastname: Decraene
authors.forename: Adel
authors.initials: A
authors.lastname: Bougatef
authors.forename: Yvan
authors.initials: Y
authors.lastname: Vandenplas
mesh_terms: D001530:Belgium; D027682:Cation Transport Proteins; D020117:Cisapride / Q000008:administration & dosage / Q000037:antagonists & inhibitors*; D004268:DNA-Binding Proteins; D000072237:ERG1 Potassium Channel; D004562:Electrocardiography; D051638:Ether-A-Go-Go Potassium Channels; D006801:Humans; D007223:Infant; D007229:Infant Welfare; D007231:Infant, Newborn; D007234:Infant, Premature; D008133:Long QT Syndrome / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000008:administration & dosage; D024642:Potassium Channels, Voltage-Gated; D012307:Risk Factors; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG; D018879:Ventricular Premature Complexes / Q000453:epidemiology / Q000209:etiology
chemical_list: D027682:Cation Transport Proteins; D004268:DNA-Binding Proteins; C072312:ERG protein, human; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C092509:KCNH6 protein, human; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG; D020117:Cisapride