title: Phenotype of Children with QT Prolongation Identified Using an Institution-Wide QT Alert System.
abstract: QT prolongation is an independent risk factor for cardiovascular mortality in adults. However, there is little information available on pediatric patients with QT prolongation and their outcomes. Herein, we evaluated the prevalence of QT prolongation in pediatric patients identified by an institution-wide QT alert system, and the spectrum of their phenotype. Patients with documented QT prolongation on an ECG obtained between November 2010 and June 2011 were included. There were 1303 pediatric ECGs, and 68 children had electrographically isolated QT prolongation. Comprehensive review of medical records was performed with particular attention to QT-prolonging clinical, laboratory, and medication data, which were summarized into a pro-QTc score. Overall, 68 (5 %) pediatric patients had isolated QT prolongation. The mean age of this pediatric cohort was 9 ± 6 years, and the average QTc was 494 ± 42 ms. All children had 1 or more QT-prolonging risk factor(s), most commonly QT-prolonging medications. One patient was identified with congenital long QT syndrome (LQTS), which was not previously diagnosed. In one-year follow-up, only one pediatric death (non-cardiac) occurred (1.5 %). Potentially QT-offending/pro-arrhythmic medications were changed in 80 % of pediatric patients after the physician received the QT alert. Children with QT prolongation had very low mortality and minimal polypharmacy. Still, medications and other modifiable conditions were the most common causes of QT prolongation. Children with a prolonged QTc should be evaluated for modifiable QT-prolonging factors. However, if no risk factors are present or the QTc does not attenuate after risk factor modification/removal, the child should be evaluated for congenital LQTS.
authors.affiliation: Department of Pediatric and Adolescent Medicine/Division of Pediatric Cardiology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Heather N
authors.initials: HN
authors.lastname: Anderson
authors.affiliation: Department of Pediatric and Adolescent Medicine/Division of Pediatric Cardiology, Mayo Clinic, Rochester, MN, USA.|Department of Molecular Pharmacology and Experimental Therapeutics/Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Guggenheim 501, 200 First Street SW, Rochester, MN, 55905, USA.|Department of Internal Medicine/Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA.
authors.forename: J Martijn
authors.initials: JM
authors.lastname: Bos
authors.affiliation: Department of Molecular Pharmacology and Experimental Therapeutics/Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Guggenheim 501, 200 First Street SW, Rochester, MN, 55905, USA.
authors.forename: Kristina H
authors.initials: KH
authors.lastname: Haugaa
authors.affiliation: Department of Health Care Policy and Research, Mayo Clinic, Rochester, MN, USA.
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Morlan
authors.affiliation: Department of Statistics, Mayo Clinic, Rochester, MN, USA.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Tarrell
authors.affiliation: Department of Internal Medicine, Division of General Internal Medicine, Mayo Clinic, Rochester, MN, USA.
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: Caraballo
authors.affiliation: Department of Pediatric and Adolescent Medicine/Division of Pediatric Cardiology, Mayo Clinic, Rochester, MN, USA. ackerman.michael@mayo.edu.|Department of Molecular Pharmacology and Experimental Therapeutics/Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Guggenheim 501, 200 First Street SW, Rochester, MN, 55905, USA. ackerman.michael@mayo.edu.|Department of Internal Medicine/Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA. ackerman.michael@mayo.edu.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Ackerman
mesh_terms: D000293:Adolescent; D053840:Brugada Syndrome / Q000175:diagnosis* / Q000401:mortality*; D000075224:Cardiac Conduction System Disease; D002648:Child; D002675:Child, Preschool; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008133:Long QT Syndrome / Q000175:diagnosis*; D008297:Male; D010641:Phenotype; D012307:Risk Factors
keywords: Long QT syndrome; Monitoring; Mortality; QT prolongation; Risk factor
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