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Congenital long QT syndrome presenting as unexplained bradycardia
  1. Rita Ataíde Silva1,
  2. Ana R Sousa1,
  3. Maria Salomé Leal de Carvalho2 and
  4. Rui Anjos1
  1. 1Department of Pediatric Cardiology, Centro Hospitalar de Lisboa Ocidental EPE, Lisboa, Carnaxide, Portugal
  2. 2Department of Cardiology, Centro Hospitalar de Lisboa Ocidental EPE, Lisboa, Carnaxide, Portugal
  1. Correspondence to Dr Rita Ataíde Silva; ritataide{at}


Congenital long QT syndrome (LQTS) is a genetically autosomal heterogeneous disorder of the ion channels and causes about 10% of sudden death infant syndrome in newborns. Its estimated prevalence is approximately 1 in 2500, probably underestimated because of its clinical heterogenicity. Few cases of neonatal LQTS have been reported. In 4% of them, life-threatening arrhythmic events can be the first manifestation of LQTS. The authors report two cases of neonatal LQTS with heterogeneous genetic mutations. Both manifested by bradycardia, one since fetal life. One case had serious arrhythmias during beta blocker therapeutic establishment needing a pacemaker implantation. Genetic mutations found were not the most frequently described in association with neonatal bradycardia, thus the importance of this report. Presentation with bradycardia is relatively frequent in neonatal period, thus LQTS should be actively investigated in neonates with unexplained bradycardia. Beta blocker therapy reduces QTc and avoids arrhythmic events and sudden death.

  • paediatrics (drugs and medicines)
  • genetics
  • neonatal health
  • congenital disorders
  • arrhythmias

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  • Contributors RAS and ARS gathered the initial clinical information and wrote the initial manuscript. MSLdC analysed all ECG tracings and corrected the manuscript. RA revised and corrected the whole manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.